Why do I keep getting 404 Errors Azure Front Door APIM and APP Service

Raymond Dunne 0

I keep receiving a 404 Error to my web app via Front Door url. I am not using custom domains. The Web App is hosted on APIM. I can call the Web App successfully through APIM url (200 Ok message through Postman)

APIM is configured as an origin in my Front door profile.

Network Security groups appear to be correct. NSG configured in APIM subnet allowing 80 and 443 from Front End

The only network configuration on the App Service side is that the App Service has been configured to use private endpoints

APIM Config APIM App Service

App Service

Many Thanks

Silvia Wibowo 3,411 Reputation points Microsoft Employee

2024-06-04T23:48:26.57+00:00

Hi @Raymond Dunne , I understand that your configuration is: Azure Front Door -> APIM -> Azure App Service (Private Endpoint).As your App Service has Private Endpoint, your APIM needs to have Outbound Integration.

Does your App Service require no authentication?
Raymond Dunne 0 Reputation points

2024-06-05T09:19:00.2966667+00:00

Hi Siliva

Thanks for the update. As APIM is configured in External Mode I don't have the option to configure APIM for Outbound VNET Integration. Have enable Web App for Outbound VNet Integration and no luck

(App is POC mock so no authentication configured yet)
Silvia Wibowo 3,411 Reputation points Microsoft Employee

2024-06-10T03:25:46.6566667+00:00
Hi @Raymond Dunne , I understand that your configuration is: Azure Front Door -> APIM (External mode) -> Azure App Service (Private Endpoint).

Your APIM should be able to access App Service using Private Endpoint.

A few things to check:

Outbound entries in NSG (Network Security Group) applied to your APIM subnet.

Inbound entries in NSG applied to your Private Endpoint (for your App Service).

What do you get if you do a test connection from your APIM to your API hosted on App Service?

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Why do I keep getting 404 Errors Azure Front Door APIM and APP Service