Google Cloud Client Libraries do not upload a file to my own drive

Question

Please help. It's my first time working with Google libraries, and I'm trying to run at least one example, but it's not working.

My goal is to upload and download a file from Google Drive. For my first test, I'm trying it on my own Google account.

I took samples from https://github.com/googleworkspace/dotnet-samples, downloaded the gcloud CLI, and ran 'gcloud auth application-default login' to log in to my Google account.

After that, the initialization started working in the samples:

GoogleCredential credential = GoogleCredential.GetApplicationDefault().CreateScoped(DriveService.Scope.Drive);

But now, when I try to upload a test file using the function below, it gives me an error:

protected string CreateTestBlob(string filePath)
{
    var fileMetadata = new Google.Apis.Drive.v3.Data.File();
    fileMetadata.Name = "photo.jpg";
    using (var stream = new FileStream(filePath, FileMode.Open))
    {
        var request = service.Files.Create(
            fileMetadata, stream, "image/jpeg");
        request.Fields = "id";
        IUploadProgress test = request.Upload();
        
        var file = request.ResponseBody;
        return "";
    }
}

The line IUploadProgress test = request.Upload(); returns an exception: "The service drive has thrown an exception. HttpStatusCode is Forbidden. Request had insufficient authentication scopes."

What does it require from me, and how can I upload a file from my computer to my Google Drive using their client libraries?