"The SPA Default Page Middleware Could Not Return" The Default Page Error While SAML Authentication

How to troubleshoot error "An error occurred while loading the external identity provider. Please check the external identity provider configuration. (#217)" ?

It is possible to find null pointer exception in the event viewer logs.

Root Cause: This error generally occurs if there is a null value in the SAML settings which has a non null Constraint in DB.

Error Message in Browser:

StatusCode":500,"StatusDescription":"InternalServerError","Message":"The SPA default page middleware could not return the default page '/index.html' because it was not found, and no other middleware handled the request.\nYour application is running in Production mode, so make sure it has been published, or that you have built your SPA manually. Alternatively you may wish to switch to the Development environment.\n


  • Check the service certificate location and ensure that it is not empty but has a value.