Application set up with Azure SSO gets 502 error on the redirect

Question

We have a VM setup in our Azure environment that hosts a Filemaker Server (for those who are familiar with Filemaker). We have configured the proper configurations with in Filemaker, and registered our application in Azure, creating Client Secrets for SSO and setting up our redirect URI. When users attempt to sign in the with SSO in our Filemaker Application, 502 - Web server received an invalid response while acting as a gateway or proxy server, is returned. Any information as to why this is being returned would be helpful.

Answer 1

Hello @Seamus Johnson,

Thank you for posting your query on Microsoft Q&A.

The issue was resolved after contacting Claris FileMaker Support (the application vendor), as it was caused by the new version of their software.

The status code 502 is a generic error that can occur for various reasons, such as:

• The request taking longer than expected to execute.
• High CPU or memory usage on the application.
• The application crashing due to multiple exceptions.

Could you please provide more details about where your application is hosted? I understand you mentioned a VM environment for the FileMaker server. Is your application hosted on Azure App Services or behind an Azure Application Gateway?

You may find the following public documentation helpful, as it outlines solution steps for resolving this error:

Azure Application Gateway Troubleshooting 502 Errors

This error may occur due to the following main reasons:

1. NSG, UDR, or Custom DNS is blocking access to backend pool members.
2. Backend VMs or instances of virtual machine scale set aren't responding to the default health probe.
3. Invalid or improper configuration of custom health probes.
4. Azure Application Gateway's backend pool isn't configured or empty.
5. None of the VMs or instances in virtual machine scale set are healthy.
6. Request time-out or connectivity issues with user requests.

You can use the troubleshooting guide to resolve 502 or 503 errors on your app service. Alternatively, you can utilize the Diagnostic and solve problems tool under your web app or enable diagnostic logs in azure app service to identify the root cause.

I hope this information is helpful. Please feel free to reach out if you have any further questions.

Please remember to "Accept Answer" if any answer/reply helped, so that others in the community facing similar issues can easily find the solution.

Thanks,
Raja Pothuraju.