Issue Deploying Next.js App to Azure App Service – Container Exited, Failing Site Start

Question

Issue Deploying Next.js App to Azure App Service – Container Exited, Failing Site Start

Tejaswini 0

24 Mar 2025, 07:51

I am trying to deploy a Next.js application to Azure App Service, but I keep encountering the following error in the log stream:

ERROR - Container b2c_0_961f87fc for site b2c has exited, failing site start

ERROR - Container b2c_0_961f87fc didn't respond to HTTP pings on port: 8080, failing site start. See container logs for debugging.

Additionally, when trying to access the application, I see this message:

:( Application Error

If you are the application administrator, you can access the diagnostic resources.

I have already tried the following troubleshooting steps:

Set the PORT environment variable in my Next.js app (process.env.PORT || 8080).

Changed the port to 3000, but the issue persists.

Verified that WEBSITES_PORT is set correctly in the Azure App Service configuration.

Checked the logs, but there are no additional details explaining why the container is exiting.

Could anyone help me identify what might be causing this issue and how to resolve it? Any guidance on debugging this further would be greatly appreciated.

Alekhya Vaddepally 240 Reputation points Microsoft External Staff

25 Mar 2025, 09:24

Hi Tejaswini,

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
Alekhya Vaddepally 240 Reputation points Microsoft External Staff

26 Mar 2025, 09:00

Hi Tejaswini,

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

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Alekhya Vaddepally 240 Reputation points Microsoft External Staff

25 Mar 2025, 09:24

Hi Tejaswini,

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
Alekhya Vaddepally 240 Reputation points Microsoft External Staff

26 Mar 2025, 09:00

Hi Tejaswini,

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

Answer 1

Alekhya Vaddepally 240 Microsoft External Staff

24 Mar 2025, 10:58

Hi Tejaswini,

Your Azure App Service has an issue with the deployed Next.js app. Specifically, the application’s container is exiting and is unable to respond to HTTP pings.

Ensure your container’s configuration file is set to listen on the correct port. You stated that the PORT environment variable was set, which is great, but also confirm that your Next.js application is configured to listen to that port as well.

If the App Service Plan is under allocated in resources like CPU and memory, the container will not run as expected. Insufficient resources can lead to unexpected container exits.

A few reasons your application can exit unexpectedly is if there are unhandled exceptions or errors in the code. To troubleshoot, try running the app locally to see if there are any issues that may not be obvious in the Azure logs.

For custom Docker containers, ensure that the configurations for DOCKER_CUSTOM_IMAGE_NAME and STARTUP_COMMAND are set.

If you have access, attempt to run the container locally with Docker first. Testing the container outside of Azure can determine if the issue is related to the Azure environment or the application.
https://learn.microsoft.com/en-us/azure/static-web-apps/deploy-nextjs-hybrid#enable-logging-for-nextjs
https://learn.microsoft.com/en-us/aspnet/core/test/troubleshoot-azure-iis?view=aspnetcore-9.0
https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/azure-iis-errors-reference?view=aspnetcore-9.0
If the answer is helpful, please click Accept Answer and kindly upvote it so that other people who faces similar issue may get benefitted from it.

Let me know if you have any further Queries.

Tejaswini 0 Reputation points

27 Mar 2025, 06:08

Hi Alekhya Vaddepally,

Thank you for your response.

The Next.js application is not using a container configuration file or Docker. The App Service Plan is on the Basic (B1) tier, and the application runs without errors when tested locally.

Since the container issue doesn't apply in this case, could you suggest any alternative troubleshooting steps specific to Next.js deployments on Azure App Service? Additionally, are there any known limitations or configurations required for Next.js apps running on the Basic (B1) tier?

Looking forward to your guidance.
Alekhya Vaddepally 240 Reputation points Microsoft External Staff

27 Mar 2025, 11:54

Hi Tejaswini,
Ensure that the build and startup commands are correctly configured in the Azure App Service.

Double-check that the Startup Command is set correctly in Azure

Go to Azure Portal → App Service → Configuration → Set NPM Run Start as General Settings → Startup Command

The Azure App service dynamically assigns a port for node.JS applications, usually through the port environment variable. Make sure your next .js app has been configured to listen to this port

In the Azure portal, go to the configuration → application settings and make sure that the websites_port variable is set correctly (usually up to 8080 or 3000).

If your next .js app uses stable files or API, make sure that the build process includes the right paths and directors.

Check whether the public/ and .next/ folders are being deployed properly.

Confirm that the relative paths for static property or API work correctly on the azure.

Check the application log to identify any runtime errors.

Go to Azure Portal → App Service → Monitoring → Log Stream.

Alternatively, use Kudu console to inspect files and logs for errors.

Verify that the Node.JS version on Azure matches the version used during local tests:

Ensure compatibility with the next .JS version specified in package.json.

https://learn.microsoft.com/en-us/azure/app-service/configure-language-nodejs?pivots=platform-linux
https://learn.microsoft.com/en-us/azure/app-service/configure-common?tabs=portal#configure-app-settings
https://learn.microsoft.com/en-us/azure/app-service/troubleshoot-diagnostic-logs
if you have any further concerns or queries, please feel free to reach out to us.

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Issue Deploying Next.js App to Azure App Service – Container Exited, Failing Site Start

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