Email problem

[M1ENT]

Thanks in advanced to anyone who can point me in the right direction.

Whenever i create a email mailbox,

i have no problems sending and receiving a email from the created mailbox. was using Thunderbird to test..

problem is, i've noticed a bunch of emails just sitting in the mail queue..

i set the mail box as webmaster@mydomain.com

the mail que says the email address is:

web1@server1.mydomain.com

anyway i can get to read the correct alias / email for web1 properly.

UPDATE:
Tried reinstalling ISPConfig3 and Reconfiguring everything.

Still have the same problem.

Emails on mailbox do work, incoming and outgoing.

emails when registering example: a wordpress website, on any domains i add to the panel gives me the actual
hostname of the server, as the email, and not the mailbox email created.

How can i fix this prob?