Utixo servers automatically detect some anomalous conditions to prevent some users from sending SPAM and somehow compromising the reputation of their IPs.
In particular, if a high percentage of messages sent in an hour fails or remains in the deferred state, this triggers the sending block.
The user therefore receives an error like this:
Sender firstname.lastname@example.org has an outgoing mail hold.
In this situation, outgoing emails are not deleted but are simply blocked in the queue.
The operations to do in this case are:
- Identify the cause of the block and eliminate it (e.g. a PC infected with a virus)
- Wait for the lock to deactivate automatically (it may take a few hours) or open a ticket to request manual unlocking.
We emphasize that unblocking is requested and spam mailings continue the next block will not be unblockable in any way until after 24 hours, make sure you have removed the cause before requesting unblocking.
The user hold is present in the file system at /etc/ outgoing_mail_hold_users