- Customers unable to set external mail address for forwarding emails sent to a non-existent users in Domains > example.com > Mail Settings:
PLESK_ERROR: The specified email address is not valid. The email address must belong to the selected domain. Only the administrator can specify external email addresses in this case.
- Outgoing Mail Control is enabled in Tools & Settings > Mail Server Settings
Only Plesk administrator can specify an external email as catch-all address when outgoing mail is limited. Any other client may use local domain only. This is done because Messages sent to catch-all addresses if they are set to external mail server (external address) will not be counted in Outgoing Mail Control.
There is only 1 workaround available: specify required external email under admin user:
1. Login to Plesk under admin user
2. Go to Domains > example.com > Mail Settings > set
For more information, visit Plesk Administrator Guide.