On cPanel server, some times when user tries to send email, he/she gets bounce back as below:

** [email protected] F=<[email protected]> R=enforce_mail_permissions: Domain abc.com has an outgoing mail suspension. Message discarded.

This happens either because bulk emailing or spamming from the sender domain.

The server automatically adds the domain to ON HOLD list.

To lift this suspension, run below command in ssh as root:

[root@host /]# whmapi1 unsuspend_outgoing_email user=cpaneluser

metadata:
command: unsuspend_outgoing_email
reason: OK
result: 1
version: 1

Sometimes the email got bounced back with the below error:

Domain example.com has an outgoing mail hold. Message will be reattempted later

Run the below command to remove the mail hold from the user:

[root@host /]# whmapi1 release_outgoing_email user=cpaneluser
---
metadata:
  command: release_outgoing_email
  reason: OK
  result: 1
  version: 1

OR grep the cPanel username/email address and if found remove it from the following files:

/etc/outgoing_mail_hold_users 
/etc/outgoing_mail_suspended_users 

Once done, restart the Exim service.

That’s all.