Bearer token doesn't work - Unauthorized

[vovkms]

Following this guide: https://github.com/microsoft/azure-devops-auth-samples/blob/master/OAuthWebSample/README.md
I was able to create an application and authorize it to access ADO on behalf of me with the following scopes: vso.code_manage vso.project
When I generate a bearer token, I can see nameid claim value equal to my userId.

However, when I use the token - I get either 401 through Rest APIs (calling https://dev.azure.com/microsoft/_apis/projects), or using the following code:

string token = "<bearer_token>";
string patToken = "<pat_token>";

VssOAuthAccessTokenCredential credentials = new VssOAuthAccessTokenCredential(token);
//VssCredentials credentials = new VssBasicCredential(string.Empty, patToken);

// Connect to Azure DevOps Services
VssConnection connection = new VssConnection(new Uri(c_collectionUri), credentials);

Console.WriteLine(connection.AuthorizedIdentity.DisplayName);

I get the following exception:
Microsoft.VisualStudio.Services.Common.VssUnauthorizedException: 'TF400813: The user ' is not authorized to access this resource. '

If I use the commented VssCredentials with PAT token with the same scope - I'm able to call both the Rest API and use this code.

[anydot]

Hi, organization admins can disable OAuth support, that then result in the above error