Email Postboxes not showing after importing Website with Plesk Migrator

I used Plesk Migrator to migrate a complete Subscription from Server A to Server B.
On Server A the Email Settings on Domain looks like this:

and on Server B it looks like this:



The Mail Service however works without any issue and i can access the Mails via Webmail and IMAP.
I also restarted the Server without any issue and cannot see anything in the Log Files.
Best regards,
Julian