Hey there.
Please make sure you have a valid token set at either the project-level Administration > General Settings > Pull Requests ) or at the organization-level ( Administration > Organization settings > Azure DevOps connectivity management ). The 401 is being returned by a call being made to Azure DevOps (this token must have permissions to read the Pull Request in question).
If you need the exact URL where the 401 is being returned (from Azure DevOps) to troubleshoot the token, I’m happy to send you the link privately.