Blazor Identity with Google Auth is not redirecting to ExternalLogin endpoint

Blazor web app with Identity and MongoDB.

Working on Google Authentication. When I click the Google login button, the /PerformExternalLogin endpoint is hit as expected.

Then it is redirected to Google's "choose an account" page.Choose the account, click Continue and then Google redirect to ExternalLogin.razor where the callback OnLoginCallbackAsync() would be executed.

But instead, the flow comes back to Login.razor with the URLhttps://localhost:7233/Account/Login?ReturnUrl=/Account/ExternalLogin?ReturnUrl=&Action=LoginCallback

My breakpoints in ExternalLogin.razor are not hit and the user is not logged in.

Source is at https://github.com/skippyV/BlazorIdentityMongoDbMatteoFabbri

This is a screenshot of Login.razor when Google comes back to it - instead of going to the callback.