The first step to troubleshoot the unauthorized access error upon receiving the Quoter Integration Error email is to navigate to Settings (granted your User Type has permissions) > Integrations > Integration Requests Status to view the Debug Message by clicking on the chat bubble icon under the Actions column:

The unauthorized access  error is most commonly associated with an inactive API Token. The next step in troubleshooting the error would be editing the Pipedrive Integration to update the API Token and reconnect the Integration:

Viewing the Edit Integration Settings for Pipedrive in this case displays the unauthorized access  error shown on the Integration Requests Status page when viewing the debug message. We can now proceed with updating the API Token and reconnecting the Pipedrive Integration by clicking Connect to Pipedrive to resolve the error:

Once the error has been resolved, we can navigate back to the Integration Requests Status page to confirm that the change has successfully allowed the data to Sync from Quoter to Pipedrive:

Clicking on the Retry this integration request will manually attempt to push the request to the Integration:

If the above action isn't taken, the Date column will indicate when the attempt will automatically be reattempted or will display when the successful attempt was pushed from Quoter to Pipedrive: