Symptoms
Recreating a subscription stall while creating the mail accounts.
Enabling the mail service after creating the subscription
example.comfails with the following error:mailmng-outgoing failed: ERROR:__main__:column name is not unique
Cause
The outgoing mail control database already contains records about the subscription with the same name.
Resolution
Connect to the server via SSH
Reconfigure the mail subsystem:
# plesk repair mail
In case the issue persists, try manually deleting the record associated with the affected subscription:
# /usr/local/psa/admin/bin/mailmng-outgoing --remove-subscription --main-domain-name=example.com