Unable to create a new mailbox or activate the email service for a domain in Plesk: mailmng-outgoing failed: ERROR:__main__:NOT NULL constraint failed

Symptoms

When creating a new mailbox or activating the email service for a domain, the operation fails with one of the following error messages:

PLESK_ERROR: Error: mailmng-outgoing failed: ERROR:__main__:NOT NULL constraint failed: vhost_ids.domain_id

PLESK_ERROR: Error: mailmng-outgoing failed: ERROR:__main__:NOT NULL constraint failed: mails.domain_id

Cause

Unclear.

Resolution

1. Connect to the Plesk server via SSH.

2. Repair the mail configuration:

   # plesk repair mail -y