"InvalidOperationException: IDX20803: Unable to obtain configuration from: '[PII is hidden]'"

We need to enable viewing of PII logs so we can see more details about the error:Add the following line in ConfigureServices() to Startup.cs

public void ConfigureServices(IServiceCollection services){    IdentityModelEventSource.ShowPII = true; //Add this line    ....

In my case, this happened while I was developing identity prototype with Identity Server on localhost environment and my authority was configured incorrectly.

I was following an example from Identity Server 4, the issue was that the Quick start example of the Identity Server 4 contain 3 projects:

• Identity Server. with endpoint => https://localhost:5001
• Api (called Resource Api or Consumer Api).
• Client.

In the example that was provided, the Identity Server was set to https with endpoint https://localhost:5001.But the Authority was in Consumer Api was set to http://localhost:5000.

So when client try to connect to Consumer Api, it gets the http://localhost:5000 address and try to look at http://localhost:5000/.well-known/openid-configuration and this does not exist. It exist only on https://localhost:5001/.well-known/openid-configuration.

So far so good.

The solution is to ensure you are using the same endpoint of the identity server on your consumer authority:

options.Authority = "https://localhost:5001";

If anyone is experiencing this during development, I was able to solve this by clearing my developer certs then recreating them.

dotnet dev-certs https --cleandotnet dev-certs https --trust