Web App Down or Reporting Errors: Kudu Not Working

Question

Problem description

I am experiencing issues with my Web App, specifically that Kudu (SCM) is not responding and authentication

Environment

`This page isn’t working

gr-prod-sn1-afd.sso.azurewebsites.windows.net is currently unable to handle this request. HTTP ERROR 500 Web App (Windows) in an unspecified region.`

What I've already tried

I have reviewed the available case details and diagnostic information, but I have not tried any troubleshooting steps yet.

Current status

I am seeking guidance on how to resolve the Kudu authentication issue and the overall Web App downtime.

Answer 1

Hello hbpaul,

Greetings! Thanks for raising this question in the Q&A forum.

The error you see is an HTTP 500 returned by the sso.azurewebsites.windows.net front end, which is the service that signs you in to Kudu (SCM) when you click Advanced Tools from the portal. Because it happens on all of your App Services and on your Consumption plan Azure Functions at the same time, the cause is unlikely to be your application code or a single app setting. It points to one of three things: a platform-side issue in the Kudu SSO service for your region, a restriction on the SCM site (for example an access restriction or public network access setting applied at subscription level), or a browser or session problem with the portal sign-in. The details you shared do not let me say which one it is, so here are steps to narrow it down.

Check Azure Service Health first. Open the Azure portal, search for Service Health, and look at Service issues and Health history for App Service in your region. If there is an active incident, the Kudu errors will clear once Microsoft resolves it. You can also create a Service Health alert so you are notified of updates.

Test the SCM site directly, bypassing the portal button. Open https://<your-app-name>.scm.azurewebsites.net in a private browser window and sign in with your Entra ID account. If it loads, the problem is limited to the portal SSO hand-off. If it also returns an error, the problem is on the SCM site itself.

Rule out a browser or session issue. Sign out of the portal, clear cookies for portal.azure.com and azurewebsites.net, or try another browser or a different network. Make sure you are signed in to the correct directory (tenant) that owns the subscription.

Check access restrictions and network settings on the SCM site. For one app, go to App Service > Networking > Access restrictions and select the "Advanced tool site" tab. Confirm your public IP is not blocked and that public network access is not disabled. Also check whether an Azure Policy such as "App Service apps should disable public network access" was recently assigned to your subscription, because it can block the SCM site.

Check that your account has permission. Kudu access needs a role that includes the Microsoft.Web/sites/publish/Action permission, for example Contributor or Website Contributor on the app. If a role assignment or a Conditional Access policy changed recently, sign-in to Kudu may fail.

Restart the app and the SCM site. From the app's Overview page, select Restart and wait a few minutes. You can also run the command below, then try Kudu again.

az webapp restart --name <APP_NAME> --resource-group <RESOURCE_GROUP>

1. Use "Diagnose and solve problems" and other tools in the meantime. Open App Service > Diagnose and solve problems and run "Availability and Performance" and "Web App Down" to see what the platform detects. For logs while Kudu is down, use Log stream, Application Insights, or the Azure CLI.

az webapp log tail --name <APP_NAME> --resource-group <RESOURCE_GROUP>

Please also note that you wrote the Web App itself is down. If that is true, check the main site URL (not the SCM URL) and look at the HTTP status it returns, because Kudu failures and site downtime can be separate problems.

If this answer helps you kindly accept the answer which will help others who have similar questions.

Best Regards,
Jerald Felix.

Answer 2

This page isn’t working

gr-prod-sn1-afd.sso.azurewebsites.windows.net is currently unable to handle this request.

HTTP ERROR 500

This when I click Development Tools ---> Advance Tools--- GO to reach KUDU

This on all my App Services. Including all my Azure Function on the consumption plan