How can I fix a 504 timeout issue in Azure App Service while deploying a CakePHP 2 application?

Question

How can I fix a 504 timeout issue in Azure App Service while deploying a CakePHP 2 application?

salman 20

Hi,

I previously deployed a CakePHP 2 application on Azure App Service, and it was working fine. Recently, we made some changes to the bootstrap.php and AmsController.php files to integrate Azure Blob Storage and Key Vault keys.

After redeploying and reloading the application, it started hanging during load and returned a 504 Gateway Timeout error. The application log file is not being updated, but the Azure log stream shows the following log output (attached below).

we reverted that 2 files (bootstrap.php and AmsController.php) still facing same issue.

Azure App service - Web

OS - Linux

Could you please help us identify the issue and suggest a fix?

AzureLog.txt

Alekhya Vaddepally 1,340 Reputation points Microsoft External Staff Moderator

2025-04-18T11:46:00.03+00:00

Hi salman,

The application is not executed within the predetermined amount of logic time. If 504 is happening before 240 seconds (which is the HTTP request time out of Azure), then it is probably being set in the application.

Review whether this timeout is showing numbers like 60 seconds, 120 seconds, 130 seconds, etc.

It can potentially be set by an SDK in use by application, or a framework specific timeout

The argument that invites external dependence can also be a case.
If an external dependence (such as a database or API) is slow, or, not refund the response in the predetermined amount of the time prescribed within the application - an HTTP 504 can show 504 If external dependence is an issue by profiling or debugging the logic within that execution reference, it can be reviewed. TCPPING can be run to check the response time for dependence. Also, to check it locally (pointing to remote dependency) to check if it occurs on both local and Azure.

Review whether it is on specific routes, or the pieces of logic are being invited

Other landscapes, such as high CPU, high memory, high I/o waiting time, high load average, or other - can contribute to HTTP 504.
Customers can use diagnosis and solve problems to rule it, such as the following detectors:

Linux CPU Drill Down

Linux memory dill down

Http server errors

Linux - Host I/O Waiting %

Linux load average
Process full list

https://learn.microsoft.com/en-us/azure/app-service/troubleshoot-http-502-http-503#504-gateway-timeout
if you have any further concerns or queries, please feel free to reach out to us.
salman 20 Reputation points

2025-04-18T12:52:24.0166667+00:00

Hi Alekhya Vaddepally,

Thank you for your response.

My server's SSH is working fine, and I’ve already tried restarting the server, but the issue still persists. We're using the Premium P1 App Service Plan, and this is a test environment — I'm the only user accessing the application at the moment.

Please let me know if there’s anything else I should check or try.

Thanks.
Alekhya Vaddepally 1,340 Reputation points Microsoft External Staff Moderator

2025-04-21T08:49:39.8+00:00

Hi salman

, 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
Sina Salam 21,226 Reputation points Moderator

2025-04-21T23:50:38.3066667+00:00
Hello salman,

Welcome to the Microsoft Q&A and thank you for posting your questions here.

I understand that you are experiencing a 504 Gateway Timeout error after making changes to bootstrap.php and AmsController.php to integrate Azure Blob Storage and Key Vault keys.

I would advise you to get more error details if you have enabled logging, navigate to App Service > Logs and enable Application Logging (Filesystem), Web Server Logging, and Detailed Error Messages.

Double-check the changes made to bootstrap.php and AmsController.php for any syntax or logical errors. This will ensure that the integration with Azure Blob Storage and Key Vault is correctly configured.

Also, test any "External Dependencies" that Azure Blob Storage and Key Vault services are accessible and not causing delays. You can use tools like TCPPING to check the response time for these dependencies.

Check all necessary environmental variables (e.g., azure_*, blob_*, keyvault_*) are correctly set and accessible.

If the app is in a service VNET, you will need to verify that DNS resolution and firewall rules are not blocking Azure service traffic.

For permanent resolution, you can create a new deployment slot and deploy a minimal version of the application without the Azure services integration and if the barebones version works, gradually reintroduce the integrations to identify the problematic component.

Finally on my list, monitor CPU, memory, and I/O usage in Azure Monitor to ensure that resource limits are not causing the issue. You can enable the "Always On" setting in Azure App Service to prevent the app from being unloaded due to inactivity.

I hope this is helpful! Do not hesitate to let me know if you have any other questions or clarifications.

Please don't forget to close up the thread here by upvoting and accept it as an answer if it is helpful.
Alekhya Vaddepally 1,340 Reputation points Microsoft External Staff Moderator

2025-04-22T08:32:20.66+00:00

Hi salman,
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

1 answer

Your answer

Alekhya Vaddepally 1,340 Reputation points Microsoft External Staff Moderator

2025-04-18T11:46:00.03+00:00

Hi salman,

The application is not executed within the predetermined amount of logic time. If 504 is happening before 240 seconds (which is the HTTP request time out of Azure), then it is probably being set in the application.

Review whether this timeout is showing numbers like 60 seconds, 120 seconds, 130 seconds, etc.

It can potentially be set by an SDK in use by application, or a framework specific timeout

The argument that invites external dependence can also be a case.
If an external dependence (such as a database or API) is slow, or, not refund the response in the predetermined amount of the time prescribed within the application - an HTTP 504 can show 504 If external dependence is an issue by profiling or debugging the logic within that execution reference, it can be reviewed. TCPPING can be run to check the response time for dependence. Also, to check it locally (pointing to remote dependency) to check if it occurs on both local and Azure.

Review whether it is on specific routes, or the pieces of logic are being invited

Other landscapes, such as high CPU, high memory, high I/o waiting time, high load average, or other - can contribute to HTTP 504.
Customers can use diagnosis and solve problems to rule it, such as the following detectors:

Linux CPU Drill Down

Linux memory dill down

Http server errors

Linux - Host I/O Waiting %

Linux load average
Process full list

https://learn.microsoft.com/en-us/azure/app-service/troubleshoot-http-502-http-503#504-gateway-timeout
if you have any further concerns or queries, please feel free to reach out to us.
salman 20 Reputation points

2025-04-18T12:52:24.0166667+00:00

Hi Alekhya Vaddepally,

Thank you for your response.

My server's SSH is working fine, and I’ve already tried restarting the server, but the issue still persists. We're using the Premium P1 App Service Plan, and this is a test environment — I'm the only user accessing the application at the moment.

Please let me know if there’s anything else I should check or try.

Thanks.
Alekhya Vaddepally 1,340 Reputation points Microsoft External Staff Moderator

2025-04-21T08:49:39.8+00:00

Hi salman

, 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
Sina Salam 21,226 Reputation points Moderator

2025-04-21T23:50:38.3066667+00:00

Hello salman,

Welcome to the Microsoft Q&A and thank you for posting your questions here.

I understand that you are experiencing a 504 Gateway Timeout error after making changes to bootstrap.php and AmsController.php to integrate Azure Blob Storage and Key Vault keys.

I would advise you to get more error details if you have enabled logging, navigate to App Service > Logs and enable Application Logging (Filesystem), Web Server Logging, and Detailed Error Messages.

Double-check the changes made to bootstrap.php and AmsController.php for any syntax or logical errors. This will ensure that the integration with Azure Blob Storage and Key Vault is correctly configured.

Also, test any "External Dependencies" that Azure Blob Storage and Key Vault services are accessible and not causing delays. You can use tools like TCPPING to check the response time for these dependencies.

Check all necessary environmental variables (e.g., azure_*, blob_*, keyvault_*) are correctly set and accessible.

If the app is in a service VNET, you will need to verify that DNS resolution and firewall rules are not blocking Azure service traffic.

For permanent resolution, you can create a new deployment slot and deploy a minimal version of the application without the Azure services integration and if the barebones version works, gradually reintroduce the integrations to identify the problematic component.

Finally on my list, monitor CPU, memory, and I/O usage in Azure Monitor to ensure that resource limits are not causing the issue. You can enable the "Always On" setting in Azure App Service to prevent the app from being unloaded due to inactivity.

I hope this is helpful! Do not hesitate to let me know if you have any other questions or clarifications.

Please don't forget to close up the thread here by upvoting and accept it as an answer if it is helpful.
Alekhya Vaddepally 1,340 Reputation points Microsoft External Staff Moderator

2025-04-22T08:32:20.66+00:00

Hi salman,
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

Hi salman,

From the SSH terminal, run the entry point manually and check the Errors. If there is a syntax or a runtime error, it will appear here.
If the process is hanging, it means that there is something blocked in the bootstrap (or CAKEPHP dispatcher).
if you rolled the bootstrap back, integration can still be referred to elsewhere, or:
Cashed configurations/Auth tokens can be invalid.
The app may still try to reach those services during the load.
Try to check:
Any key related to environmental variables - azure_*, blob_*, keyvault_*, etc. Network Settings - If your app is in service VNET, make sure that DNS resolution and firewall rules are not blocking Azure service traffic. Try to remove those services from your environment temporarily to separate this issue.
This is a great way of troubleshooting without affecting your main slot: Go to app service → add the deployment slot → slot.
Clone your current configuration and deploy a barebones version of your app (no Azure service, no heavy boot logic). See what the new slot works, If it loads fine, the problem is in the current environment or code of your app.
Make sure logging is enabled so you can catch PHP errors:
App Service → Logs
- Application Logging (Filesystem): On
- Web Server Logging: On
- Detailed Error Messages: On

Check output via Log Stream or directly from /home/LogFiles.

if you have any further concerns or queries, please feel free to reach out to us.

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How can I fix a 504 timeout issue in Azure App Service while deploying a CakePHP 2 application?

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