Why does my static web app respond with 500?

Question

Why does my static web app respond with 500?

Oblio 51

... and how do I troubleshoot that?

I have a static web app hosted in Azure that has a 'release candidate' environment. I've deployed my app to both; they both show a status of "ready". I can reach the app on the 'release candidate' environment when I click the 'browse' link. However, when I do the same on the 'production' slot, I get a "500: Internal Server Error" azure page. How do I troubleshoot that? There's no log to review. The app clearly works under the other environment and it's the same code. What's the underlying error?

Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-03-20T05:24:45.2166667+00:00

Hi @Oblio

Can you please share your Production yml file and what is your Build Presets (ex: react or Nextjs or blazor).
Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-03-21T05:01:06.7866667+00:00

Hi @Oblio

Just checking in! Were you able to look into the details I mentioned? If you can share your production YAML file and build preset (React, Next.js, Blazor, etc.), I’d be happy to help troubleshoot further. Also, let me know if you’ve noticed any differences in environment variables between the two environments.
Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-03-24T04:03:59.34+00:00

Hi @Oblio
Just checking in! Were you able to look into the details I mentioned? If you can share your production YAML file and build preset (React, Next.js, Blazor, etc.), I’d be happy to help troubleshoot further. Also, let me know if you’ve noticed any differences in environment variables between the two environments.
Oblio 51 Reputation points

2025-03-28T12:38:42.2366667+00:00

Can you be more specific? What is the production YAML? The app is written in react, but I don't know what you mean by "build preset".

Oblio 51

I think you're looking for the YAML of the deployment task? Here is the comparison between the two. Please note: this is being performed in the release pipeline not the build. It looks like the "task" is basically the same, though - the info link goes to the same location.

User's image

The release YAML (which runs correctly) looks like this:

task: AzureStaticWebApp@0

displayName: 'deploy static web app to release-candidate slot'

inputs:

  workingDirectory: '$(System.DefaultWorkingDirectory)/<publish object path>/frontend'

  app_location: /dist

  config_file_location: ./

  skip_app_build: true

  skip_api_build: true

  is_static_export: false

  verbose: false

  azure_static_web_apps_api_token: '$(AZURE_STATIC_WEB_APPS_API_TOKEN)'

  deployment_environment: 'release-candidate'

The production YAML (which returns 500) looks like this:

task: AzureStaticWebApp@0

displayName: 'deploy static web app to production slot'

inputs:

  workingDirectory: '$(System.DefaultWorkingDirectory)/<publish object path>/frontend'

  app_location: /dist

  config_file_location: ./

  skip_app_build: true

  skip_api_build: true

  is_static_export: false

  verbose: false

  azure_static_web_apps_api_token: '$(AZURE_STATIC_WEB_APPS_API_TOKEN)'

Basically, the build is performed in the build pipeline. I just need to deploy all the assets under /frontend/dist to the SWA. Same code to both preview environments.

Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-04-02T03:35:16.38+00:00

Hi @Oblio

"Build preset" refers to a framework such as React, Next.js, or Angular.

Kantamsetti Aslesha 250 Microsoft External Staff

Hi @Oblio

I tried your YAML file and successfully deployed the sample React app to both the Production and Preview environments without any issues.

Make sure to specify the correct directory and file name in your YAML file, and ensure that the staticwebapp.config.json file is properly configured.

{
  "navigationFallback": {
    "rewrite": "/index.html",
    "exclude": ["/api/*"]
  }
}

Please try deploying a sample React app to Azure Static Web Apps and check if it is working.

Below is my sample YAML file:

trigger:
  branches:
    include:
      - main  # Runs on every push to main
pool:
  vmImage: 'ubuntu-latest'
stages:
  - stage: Deploy_ReleaseCandidate
    displayName: 'Deploy to Release-Candidate'
    jobs:
      - job: DeployReleaseCandidate
        displayName: 'Deploy to Release-Candidate Environment'
        steps:
          - task: AzureStaticWebApp@0
            displayName: 'Deploy to release-candidate slot'
            inputs:
              app_location: 'build'  # Use 'dist' folder
              config_file_location: './'  # Assumes staticwebapp.config.json is in root
              skip_app_build: true
              skip_api_build: true
              is_static_export: false
              verbose: false
              azure_static_web_apps_api_token: '$(AZURE_STATIC_WEB_APPS_API_TOKEN)'
              deployment_environment: 'release-candidate'
  - stage: Deploy_Production
    displayName: 'Deploy to Production'
    dependsOn: Deploy_ReleaseCandidate
    condition: succeeded()
    jobs:
      - job: DeployProduction
        displayName: 'Deploy to Production Environment'
        steps:
          - task: AzureStaticWebApp@0
            displayName: 'Deploy to production slot'
            inputs:
              app_location: 'build'  # Use 'dist' folder
              config_file_location: './'  # Assumes staticwebapp.config.json is in root
              skip_app_build: true
              skip_api_build: true
              is_static_export: false
              verbose: false
              azure_static_web_apps_api_token: '$(AZURE_STATIC_WEB_APPS_API_TOKEN)'

2025-04-02 12_58_11-kareactdevopsapp - Microsoft Azure and 11 more pages - Work - Microsoft Edge

2025-04-02 13_01_21-React App and 11 more pages - Work - Microsoft Edge

2025-04-02 13_02_14-React App and 11 more pages - Work - Microsoft Edge

Oblio 51 Reputation points

2025-04-02T16:04:44.2666667+00:00
It's good to know it works, but I'm not sure where to look for the problem. Some differences are:

the app is different, of course. I'm not deploying the react sample app. But that shouldn't matter here.

the deployment task is different. Again, I'm not doing it from the build pipeline, I'm doing it from the release pipeline. Theoretically that shouldn't matter either; I think they both use the same code under the hood, but I don't know for sure.

the output is coming from a pipeline artifact. Again, this shouldn't matter as the build is skipped.
Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-04-04T05:56:42+00:00

Hi @Oblio

Are you adding any environment variables to your Azure Static Web App such as AzureWebJobsStorage ,FUNCTIONS_EXTENSION_VERSION ,FUNCTIONS_WORKER_RUNTIME ? If yes please remove this variables and deploy again.

2 answers

Your answer

Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-03-20T05:24:45.2166667+00:00

Hi @Oblio

Can you please share your Production yml file and what is your Build Presets (ex: react or Nextjs or blazor).
Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-03-21T05:01:06.7866667+00:00

Hi @Oblio

Just checking in! Were you able to look into the details I mentioned? If you can share your production YAML file and build preset (React, Next.js, Blazor, etc.), I’d be happy to help troubleshoot further. Also, let me know if you’ve noticed any differences in environment variables between the two environments.
Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-03-24T04:03:59.34+00:00

Hi @Oblio
Just checking in! Were you able to look into the details I mentioned? If you can share your production YAML file and build preset (React, Next.js, Blazor, etc.), I’d be happy to help troubleshoot further. Also, let me know if you’ve noticed any differences in environment variables between the two environments.
Oblio 51 Reputation points

2025-03-28T12:38:42.2366667+00:00

Can you be more specific? What is the production YAML? The app is written in react, but I don't know what you mean by "build preset".
Oblio 51 Reputation points

2025-03-31T15:16:06.77+00:00

I think you're looking for the YAML of the deployment task? Here is the comparison between the two. Please note: this is being performed in the release pipeline not the build. It looks like the "task" is basically the same, though - the info link goes to the same location.

The release YAML (which runs correctly) looks like this:

task: AzureStaticWebApp@0 displayName: 'deploy static web app to release-candidate slot' inputs: workingDirectory: '$(System.DefaultWorkingDirectory)/<publish object path>/frontend' app_location: /dist config_file_location: ./ skip_app_build: true skip_api_build: true is_static_export: false verbose: false azure_static_web_apps_api_token: '$(AZURE_STATIC_WEB_APPS_API_TOKEN)' deployment_environment: 'release-candidate'

The production YAML (which returns 500) looks like this:

task: AzureStaticWebApp@0 displayName: 'deploy static web app to production slot' inputs: workingDirectory: '$(System.DefaultWorkingDirectory)/<publish object path>/frontend' app_location: /dist config_file_location: ./ skip_app_build: true skip_api_build: true is_static_export: false verbose: false azure_static_web_apps_api_token: '$(AZURE_STATIC_WEB_APPS_API_TOKEN)'

Basically, the build is performed in the build pipeline. I just need to deploy all the assets under /frontend/dist to the SWA. Same code to both preview environments.
Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-04-02T03:35:16.38+00:00

Hi @Oblio

"Build preset" refers to a framework such as React, Next.js, or Angular.
Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-04-02T07:34:38.4566667+00:00

Hi @Oblio

I tried your YAML file and successfully deployed the sample React app to both the Production and Preview environments without any issues.

Make sure to specify the correct directory and file name in your YAML file, and ensure that the staticwebapp.config.json file is properly configured.

{ "navigationFallback": { "rewrite": "/index.html", "exclude": ["/api/*"] } }

Please try deploying a sample React app to Azure Static Web Apps and check if it is working.

Below is my sample YAML file:

trigger: branches: include: - main # Runs on every push to main pool: vmImage: 'ubuntu-latest' stages: - stage: Deploy_ReleaseCandidate displayName: 'Deploy to Release-Candidate' jobs: - job: DeployReleaseCandidate displayName: 'Deploy to Release-Candidate Environment' steps: - task: AzureStaticWebApp@0 displayName: 'Deploy to release-candidate slot' inputs: app_location: 'build' # Use 'dist' folder config_file_location: './' # Assumes staticwebapp.config.json is in root skip_app_build: true skip_api_build: true is_static_export: false verbose: false azure_static_web_apps_api_token: '$(AZURE_STATIC_WEB_APPS_API_TOKEN)' deployment_environment: 'release-candidate' - stage: Deploy_Production displayName: 'Deploy to Production' dependsOn: Deploy_ReleaseCandidate condition: succeeded() jobs: - job: DeployProduction displayName: 'Deploy to Production Environment' steps: - task: AzureStaticWebApp@0 displayName: 'Deploy to production slot' inputs: app_location: 'build' # Use 'dist' folder config_file_location: './' # Assumes staticwebapp.config.json is in root skip_app_build: true skip_api_build: true is_static_export: false verbose: false azure_static_web_apps_api_token: '$(AZURE_STATIC_WEB_APPS_API_TOKEN)'
Oblio 51 Reputation points

2025-04-02T16:04:44.2666667+00:00

It's good to know it works, but I'm not sure where to look for the problem. Some differences are:

the app is different, of course. I'm not deploying the react sample app. But that shouldn't matter here.

the deployment task is different. Again, I'm not doing it from the build pipeline, I'm doing it from the release pipeline. Theoretically that shouldn't matter either; I think they both use the same code under the hood, but I don't know for sure.

the output is coming from a pipeline artifact. Again, this shouldn't matter as the build is skipped.
Kantamsetti Aslesha 250 Reputation points Microsoft External Staff

2025-04-04T05:56:42+00:00

Hi @Oblio

Are you adding any environment variables to your Azure Static Web App such as AzureWebJobsStorage ,FUNCTIONS_EXTENSION_VERSION ,FUNCTIONS_WORKER_RUNTIME ? If yes please remove this variables and deploy again.

Answer 1

Dillon Silzer 57,826 Volunteer Moderator

Hello Oblio:

I would recommend going to your Application Insights or Diagnostic Logs under the Monitoring section of your App Service. You may have to enable this feature to get more insight into your application.

If this is helpful please accept as answer or upvote.

Best regards,

Dillon Silzer | Cloudaen.com | Cloudaen Computing Solutions

Oblio 51 Reputation points

2025-03-12T18:15:33.1+00:00

My "application insights" page says

"App Insights is only applicable to Static Web Apps with at least one function. Add a function to your app to enable App Insights. "

So, it's not an option.
Siva Nair 2,340 Reputation points Microsoft External Staff Moderator

2025-03-13T11:31:31.4866667+00:00

Hi Oblio,

Noted, Lets see few ways to troubleshoot, In addition to Dillon Silzer response,

Enable and review diagnostic logging settings available in the Azure portal for your static web app. These settings might help capture more detailed error information even without Application Insights.

Double-check that all your configuration settings and environment variables are exactly the same between your production and release candidate environments. Sometimes even a small discrepancy can cause errors.

We can use browser’s developer tools to inspect the network requests. Look at the failed request in the network tab to see if the response provides any hints about what's going wrong. This can help you identify whether a particular file or API call is causing the error.

Another approach is to replicate your production environment locally. Using tools like the Static Web Apps CLI, you can run your app on your local machine and see if any error messages appear during runtime. This local testing might reveal issues that aren’t visible in the production deployment.

consider redeploying your production slot or performing a slot swap. Sometimes stale artifacts or caching issues can result in errors, and a clean deployment might resolve the problem.

If you have any further assistant, do let me know.
Siva Nair 2,340 Reputation points Microsoft External Staff Moderator

2025-03-13T22:31:12.3866667+00:00

Hi Oblio,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution, please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Oblio 51 Reputation points

2025-03-14T02:20:01.38+00:00

I cannot perform a swap because SWAs don't offer that function. Similarly I don't see "diagnostic logging" in a SWA - can you tell me where to find that? I'm not using environment variables. I would use the browser's debugging, but I'm getting Azure's custom 500 page rather than my app, so that's not a help. I can try redeploying to the prod environment, but it's the same code between prod and the other preview environment.
Siva Nair 2,340 Reputation points Microsoft External Staff Moderator

2025-03-17T07:50:56.2833333+00:00
Hi Oblio,

Lets check few more points below,

If your SWA uses Azure Functions for backend APIs, check the Function log stream in the Azure Portal or integrate Application Insights for more detailed error tracing.

Compare the production deployment logs (from GitHub Actions or your CI/CD pipeline) with those from the preview environment to identify any discrepancies during the build or deployment process.

Try accessing API endpoints directly (e.g., https://<yourapp>.azurestaticapps.net/api/your-endpoint) to see if they return more informative errors.

If possible, include more detailed error logging in your application code temporarily, so you can capture the actual error message before the custom 500 page is displayed.

Verify that your routes.json or staticwebapp.config.json files are correctly configured in production and that there aren’t any case sensitivity or path issues affecting production.

If you have any further assistant, do let me know.
Siva Nair 2,340 Reputation points Microsoft External Staff Moderator

2025-03-18T01:00:07.5+00:00

Hi Oblio,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution, please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Siva Nair 2,340 Reputation points Microsoft External Staff Moderator

2025-03-19T00:05:56.85+00:00

Hi Oblio,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution, please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Oblio 51 Reputation points

2025-03-19T14:09:02.0133333+00:00
It does not contain any code for an API so there's no log to check. Besides, as far as I can tell, the frontend would have to reach the browser in order to get a call to one of those APIs.

The deployment is the same. I'm using a release pipeline in DevOps that references the same pipeline artifact that's deployed to the preview environment. This means two things: the code is precisely the same and it's already pre-built (does not need/use the Oryx tool in SWA).

Again, no APIs.

Again, no function code. Also, the SWA does not appear to have a logging facility beyond the Application Insights.

Not sure how they would be configured differently for production vs a preview environment, or how that would affect it working. Also don't know how that would result in the SWA returning a 500. As I said, I've deployed precisely the same code to both "production" and my preview environment (called "release-candidate). At least, I believe I have - I don't have a way to verify that has occurred because I'm getting a 500 error when browsing.
Siva Nair 2,340 Reputation points Microsoft External Staff Moderator

2025-03-20T14:02:17.9966667+00:00

Hi Oblio,

sorry for the inconvenience you are facing. And thank you for the inputs above. just trying to cover every possible scenario to resolve your issue.

Since there are no APIs or functions, the 500 error is likely caused by a deployment issue, corrupted files, or routing misconfigurations. You can clear the Azure CDN cache from the portal (Configuration → Reset Content Cache) to rule out caching issues.

Even if the same artifact is used, deployments can fail silently. Check the Deployment History in the Azure Portal under the Static Web App to ensure the latest deployment was successful and without errors.

Confirm that the correct artifact was deployed using the URL /_latest/artifact. Compare the results in both environments (production and release-candidate). If the timestamps or artifact details differ, redeploy using your Azure DevOps pipeline.

Even with the same code, production may have unique configurations like custom domains or SSL settings. Verify domain mappings under Custom Domains in the Azure Portal and check for any SSL or DNS-related issues.

Ensure your staticwebapp.config.json or routes.json is correctly configured. If the index.html isn’t served by default, add one. Misconfigured routes can result in a 500 error.

Directly access static files like /index.html or /logo.png. A 404 or 500 error may indicate a missing file or failed deployment. If files are inaccessible, redeploy using the pipeline to ensure all files are present.

Please refer troubleshooting doc - https://learn.microsoft.com/en-us/azure/static-web-apps/troubleshooting

If you have any further assistant, do let me know.
Oblio 51 Reputation points

2025-03-28T12:36:18.8533333+00:00

Apologies for the delay getting back to this.

Under SWA ->Settings ->Configuration, there is nothing that reads "reset content cache"

Clicking the link next to "deployment history" does nothing. This is likely because it seems to link to "Azure DevOps pipeline runs", which I'm not using.

The /_latest/artifact path works fine in the releasecandidate, but results in a 500 on production.

I'm only using the Azure provided URL.

I believe my staticwebapp.config.json is correct. The navigationFallback is set to rewrite to index.html as it's a SPA.

I've tried hitting a file directly, but nothing is returned, only 500.

Answer 2

Hi @Oblio

I'm glad that you were able to resolve your issue and thank you for sharing the solution with us, so that others experiencing the same thing can easily reference this!

Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll post your solution in case you'd like to "Accept " the answer.

Issue :

After deploying a static web app to Azure, the 'release candidate' environment worked as expected, but the 'production' slot returned a 500: Internal Server Error when accessed. Both environments showed a Ready status, and the same code was deployed to both, making the issue unclear due to the lack of logs or detailed error output.

Solution :

The exact cause of the 500 error in the production slot was not visible, and Azure Static Web Apps doesn't provide detailed logs for these types of errors out of the box. To resolve the issue, a new Azure Static Web App was created, and the app was redeployed through the release pipeline. This resolved the issue, suggesting the original app may have had a hidden misconfiguration or corrupted deployment state.

Please click Accept Answer and kindly upvote it so that other people who faces similar issue may get benefitted from it.

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Why does my static web app respond with 500?

2 answers

Your answer