TODO:

If you are using an ApiKey supplied from the server add the following to your appsettings.json file in wwwroot:

{
  "ArcGISApiKey": "YourAPIKey"
} 

Otherwise, you can delete the appsettings.json file in wwwroot and remove the following line from the program.cs file

builder.Services.AddSingleton<IConfiguration>(_ => builder.Configuration);