This has suddenly started happening and is for all new accounts. When plesk creates a new domain - it also creates a new mailenable postoffice with the domain name - but now it doesnt create the domain for the post office. Customers can create mailboxes thru plesk but they dont work because they are not associated with any domain name in mailenable. We are now manually adding the domain names to new accounts in the mailenable admin. As usual, we have done nothing that would cause this. Our plesk installation is based on a clean windows 2003 install and we have not made any changes.