I am using following service code to retrieve folders of the users.
I enabled the drive api and want to use service account…

There are folders in drive but Execute returns none.

What might be missing?

using Google.Apis.Auth.OAuth2;
using Google.Apis.Drive.v3;
using Google.Apis.Services;

namespace GoogleDriveService.Business.Services;

public class GoogleApiDriveService
{
    private DriveService _driveService;

    public GoogleApiDriveService()
    {
        var credentialsFilePath = "myservice-12aaae22210a.json";
        GoogleCredential credential = GoogleCredential.FromFile(credentialsFilePath)
                                                      .CreateScoped([DriveService.Scope.Drive,
                                                                    DriveService.Scope.DriveFile,
                                                                    DriveService.Scope.DriveReadonly]);

        var initializer = new BaseClientService.Initializer { HttpClientInitializer = credential };
        _driveService = new DriveService(initializer);
    }

    public List<Google.Apis.Drive.v3.Data.File> GetFolders()
    {
        var request = _driveService.Files.List();
        request.IncludeItemsFromAllDrives = true;
        request.SupportsAllDrives = true;
        request.Q = "mimeType='application/vnd.google-apps.folder'";

        var result = request.Execute();
        return result.Files.ToList();
    }
}

I enabled the drive api, download the service account key, and run the code.