Receiving 401 Unauthorized when attempting to list users with JWT Token

I am following the tutorial from this page: How to get an access token with Implicit Grant | Docusign

I have an href to the following URL: https://account-d.docusign.com/oauth/auth?response_type=code&scope=impersonation%20signature%20organization_read%20user_read%20account_read%20dtr.profile.read&client_id=#redacted#&redirect_uri=https://localhost:7054/dsauth

When I follow this href I am directed to log in and grant permission.  I am successfully redirected back to https://localhost:7054/dsauth.  I capture the token from the “code” query parameter.

When I try to use that token in the header to list users, I receive 401 unauthorized.  I can’t find any documentation to help resolve the problem, and as far as I can tell I’m following the example perfectly.

I am using C# and RestSharp to make the calls.  Following is the relevant code:

    async void GetUsers()
    {
        var client = new RestClient("https://account-d.docusign.com/oauth/userinfo");
        var request = new RestRequest();
        request.Method = Method.Get;
        request.AddHeader("Authorization", $"Bearer {AccessToken}");

        var response = await client.ExecuteAsync(request);

        if (response.IsSuccessful)
        {
            // Handle successful response
            result = response.Content;
        }
        else
        {
            // Handle error response
            result = response.ErrorMessage;
        }
    }

I’m frustrated and out of ideas.  Any help is appreciated.  Even just a link to relevant documentation.  I’ve tried adding any scope even remotely relevant, and it’s not changing anything.  I can’t see any options in my App Registration screen that seems relevant.