Blazor WASM - OIDC Authentication - There was an error trying to log you in: 'Cannot read properties of undefined (reading 'redirectUri')' - amazon-cognito

Question

I am changing an existing Blazor Web Assembly app from AzureAD authentication to another OIDC provider (AWS Cognito).
I used these instructions from Microsoft to perform the change. https://learn.microsoft.com/en-us/aspnet/core/blazor/security/webassembly/standalone-with-authentication-library?view=aspnetcore-6.0&tabs=visual-studio
However, when I tried to press the Log In button, I got an error message
There was an error trying to log you in: 'Cannot read properties of
undefined (reading 'redirectUri')'
I couldn't find any other documentation on this error that covered this exact case, so once I found out what the problem was, I decided to create this post to help others that might hit the same problem.
On first reading, I identified that primary change that I needed to make was to change
Client.Program.cs (delete the following)
builder.Services.AddMsalAuthentication(options =>
{
builder.Configuration.Bind("AzureAd", options.ProviderOptions.Authentication);
options.ProviderOptions.DefaultAccessTokenScopes.Add("api://api.id.uri/access_as_user");
});
Client.Program.cs (add the following)
builder.Services.AddOidcAuthentication(options =>
{
options.ProviderOptions.Authority = builder.Configuration["Aws:Authority"];
options.ProviderOptions.ClientId = builder.Configuration["Aws:ClientId"];
options.ProviderOptions.ResponseType = "code";
});
Add the following section to Client.wwwroot.appsettings.json
{
/*
The following identity settings need to be configured
before the project can be successfully executed.
For more info see https://aka.ms/dotnet-template-ms-identity-platform
"Aws": {
"Authority": "https://oidc-provider-authority",
"ClientId": "oidc-provider-clientid",
"ValidateAuthority": true
}
}

Answer 1

After a fair bit of investigation, I identified that I missed an important part of the instructions.
I also needed to replace the following on Index.html:
<script src="_content/Microsoft.Authentication.WebAssembly.Msal/AuthenticationService.js"></script>
with
<script src="_content/Microsoft.AspNetCore.Components.WebAssembly.Authentication/AuthenticationService.js"></script>
Once I made this change, the authentication worked and I was redirected to the signin page of my OIDC provider.