There's an email account that receives emails without any problems but it returns a mail delivery error to senders:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

pipe to |/usr/local/cpanel/3rdparty/mailman/mail/mailman post xxxx_domain.com
generated by xxxx@domain.com
local delivery failed

The following text was generated during the delivery attempt:

------ pipe to |/usr/local/cpanel/3rdparty/mailman/mail/mailman post xxxx_domain.com
generated by xxxx@domain.com ------

post script, list not found: xxxx@domain.com

I have deleted and re-created the email account and the problem persists, this hosting account has never had mailman activated, and is the only one with this problem, the other email accounts work just fine.

I would appreciate any comments, suggestions or ideas on this matter.