Azure App Service gives 504 - Gateway Timeout Issue

Question

Azure App Service gives 504 - Gateway Timeout Issue

Dinesh Kumar Sai M 0

I am hosting APIs with App Service. The API backend is build with Python Fast API Framework, the configuration:

OS : Linux
Stack : Python
Major Version : Python - 3

Minor Version : Python - 3.12

User's image

Its running fine for some hours while started/restarted, but after sometime its giving 504 gateway timeout error. Again needs to restart to host the API. The API needs to serve for all the time, no timeout should be set.

Alekhya Vaddepally 1,670 Reputation points Microsoft External Staff Moderator

2025-03-06T10:15:02.0133333+00:00

Hi Dinesh Kumar Sai M,

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 1,670 Reputation points Microsoft External Staff Moderator

2025-03-07T10:13:22.6466667+00:00

Hi Dinesh Kumar Sai M,

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 1,670 Reputation points Microsoft External Staff Moderator

2025-03-06T10:15:02.0133333+00:00

Hi Dinesh Kumar Sai M,

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 1,670 Reputation points Microsoft External Staff Moderator

2025-03-07T10:13:22.6466667+00:00

Hi Dinesh Kumar Sai M,

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 1,670 Microsoft External Staff Moderator

Hi Dinesh Kumar Sai M,

The 504 Gateway Timeout error in Azure App Service usually happens when the application doesn't respond within the set timeout period.

This is common when hosting APIs. Here are some solutions may help keep your responsive and reduce 504 gateway time out errors

Need to check azure app service have enough resources like having basic (b1, b2), standard (s1, s2) tier, and also check your CPU memory usage in Azure Monitor to check if resource limits are causing the issue.

Azure App Service may scale down or unload your app if it's inactive. To avoid this, you can also enable “Always on” in Azure portal> App Service >Configuration > General Settings

You can also increase timeout by default 20 seconds in azure application gateway by configuring the backendhttpsettings.

Use the AutoHeal feature to recycle automatically the worker process based on triggers, which can help with memory leaks

If your API calls are taking too long, consider optimizing database queries, caching responses, or using background tasks in Fast API.

Use Azure Application Insights to check which API calls are slow

https://learn.microsoft.com/en-us/azure/application-gateway/application-gateway-troubleshooting-502#request-time-out

https://learn.microsoft.com/en-us/azure/frontdoor/troubleshoot-issues#http-504-error-gateway-timeout

https://learn.microsoft.com/en-us/azure/app-service/troubleshoot-http-502-http-503#troubleshoot-http-errors-of-502-bad-gateway-and-503-service-unavailable-in-azure-app-service

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.

Dinesh Kumar Sai M 0 Reputation points

2025-03-25T05:45:58.88+00:00

Hi @Alekhya Vaddepally ,

I have Basic B1 plan, "Always On" also enabled but still facing same after sometime. How can I increase the Timeout in App Services
Dinesh Kumar Sai M 0 Reputation points

2025-03-25T05:47:19.7333333+00:00

Hi @Alekhya Vaddepally
I have Basic B1 plan, "Always On" also enabled but still facing same after sometime. How can I increase the Timeout in App Services or how to resolve this issue.
Alekhya Vaddepally 1,670 Reputation points Microsoft External Staff Moderator

2025-03-25T09:50:13.4733333+00:00

Hi Dinesh Kumar Sai M,

To increase the timeout in Azure App Services, you can adjust the request timeout settings in the Application Gateway if you are using one. By default, the timeout interval is set to 20 seconds. You can configure this setting via the BackendHttpSetting for your Application Gateway. Here is an example of how to set the request timeout to 60 seconds using Azure PowerShell

New-AzApplicationGatewayBackendHttpSettings -Name 'Setting01' -Port 80 -Protocol Http -CookieBasedAffinity Enabled -RequestTimeout 60

or If you are not using an Application Gateway you can upgrade your plan and to standard or higher tier which as higher cpu and memory limit, auto scaling capability and better performance and request handling
https://learn.microsoft.com/en-us/azure/application-gateway/application-gateway-troubleshooting-502#request-time-out
https://learn.microsoft.com/en-us/azure/app-service/manage-scale-up
if you have any further concerns or queries, please feel free to reach out to us.

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Azure App Service gives 504 - Gateway Timeout Issue

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