I have implemented next-auth v5 into my Next.js application and everything is working fine locally; however, after I deploy to my Azure App Service, it no longer works. After I select my Microsoft Entra ID account (formerly Azure Active Directory account), I get an error indicating HTTP ERROR 404 for my-application.azurewebsites.net/api/auth/callback/microsoft-entra-id?code=long-code. I have attached redacted screenshots of it working on localhost and not working when deployed to the Azure App Service.

Localhost:

• authorize call is successful
• reprocess call is successful
• /api/auth/callback/microsoft-entra-id call is successful
• everything works as expected

Azure App Service:

• authorize call is successful
• reprocess call is successful
• /api/auth/callback/microsoft-entra-id call fails: 404 Not Found

Network tab of failing calls

Binaries:

• Node: 20.12.2 – C:Program Filesnodejsnode.EXE
• npm: 10.5.0 – C:Program Filesnodejsnpm.CMD
  Browsers:
• Edge: Chromium (123.0.2420.81)
• Internet Explorer: 11.0.22621.1
  npmPackages:
• next: ^14.1.0 => 14.2.3
• next-auth: ^5.0.0-beta.18 => 5.0.0-beta.18
• react: ^18 => 18.2.0

I did try to hit the dynamic route directly: my-application.azurewebsites.net/api/auth/callback/microsoft-entra-id?code=abcd&session_state=1234 and originally I got a redirect to:

• https://0.0.0.0/api/auth/error?error=Configuration

I then did a little searching through the documentation and found the AUTH_URL environment variable and set that to: my-application.azurewebsites.net/api/auth

After that when I hit my-application.azurewebsites.net/api/auth/callback/microsoft-entra-id?code=abcd&session_state=1234 I get an appropriate error screen indicating: Server error There is a problem with the server configuration. Check the server logs for more information.

I did check the server logs and they report: InvalidCheck: PKCE code_verifier cookie was missing.. Read more at errors.authjs.dev#invalidcheck which makes sense because my code and session_state query parameters are bogus.

However, when I go through the normal authentication flow, I still get the same HTTP ERROR 404 when it calls: my-application.azurewebsites.net/api/auth/callback/microsoft-entra-id?code=

I do see in the logs: [auth][warn][env-url-basepath-redundant][0m Read more: warnings.authjs.dev#env-url-basepath-redundant, but I don’t set authConfig.basePath myself at all.