Overview
If the below event is being logged within Event logs for a TaskCentre Task, this does indicate issues with the Mailbox being used.
QuotaExceededException.MapiExceptionQuotaExceeded; Failed to process message due to a permanent exception with message Cannot submit message.
This needs to be rectified internally by the Exchange Administrator. The message suggests that it is due to the Mailbox quota being at full capacity.
⚠️Important: Unfortunately, we have no involvement here as the message suggests an issue with either the SMTP Mailbox or the recipient's mailbox being full, so the SMTP server is unable to deliver the message.
we recommend that you take this forward internally with your IT team.