When an object is deleted from the Sophos Cloud console and Sophos isn't removed from the endpoint beforehand, the endpoint stops being able to update.
MCS Communication reports in Endpoint Self Help that the updating failed due to Error 401: Unauthorized.
The Sophos Client doesn't reflect an error or problem with updating and doesn't alert the end user to the fact that the Sophos Client is compromised. This causes the possibility of "lost endpoints" with no obvious indications of a need for repair.
Please modify the behavior of the endpoint to raise an alert on the local system so the user will be informed of a failure and the need to contact support.