If you’re using Plesk on a Windows Server, you might get to see the following error:
Unable to create MailManager object: mailmng failed: MEAOPO.Mailbox.AddMailbox failed
You’ll get this error, probably because you’re trying to create a new mailbox for an e-mail address that was once an alias to another mailbox, but was removed.
Example: you have the mailbox “john@domain.com”, and you added an alias called “info@domain.com” to this address. Now you want to create a different mailbox for “info@domain.com”, so you delete the alias from “john@domain.com”, to create a new mailbox. That’s probably when you’ll see this error.
Solution:
Log in remotely to your windows server where the Plesk is installed, and browse to “C:\Program Files\SWsoft\Plesk\Mail Servers\Mail Enable\Config\Postoffices<your domain>".
You’ll find 3 files there, called “default.mai", “mailbox.sav” and “mailbox.tab". Open each one with notepad or wordpad, or another text editor, and find every line that says “info@domain.com” (this is the alias you once created, but are now trying to remove completely, in order to create the mailbox). You’ll see them occur in those files (it’s possible you’ll only find it in one of those 3).
Delete each line that has that e-mail address in it.
Now try to re-create the new mailbox through the Plesk web interface, you’ll see it no longer generates an error but creates the mailbox as you would expect.