Major Email problems

I am having major email problems…My pop mail reader , Mac Mail OS 10.3, cannot retrieve mail. When I attempt to sign in, it asks me for my password, which is correct, and never lets me in. This is even more frustrating because support is not answering any of my many emails. I am just switching over to dreamhost now and considering bringing about 6 domains with me but now I am reconsidering this decision.
Is anyone having similar problems?

Yes, in fact you somehow managed to miss the thread that was right at the top of this category.
I don’t work here. I’m just your typical support forum volunteer.

A common cause of this failure is the mailbox login name being different
from the FTP username & email address username. See Mail > Addresses
"Login" to find the mailbox login name. (The DH m######-style mailboxes
have various shortcomings - you’d be better off using a so-called
user mailbox instead. Create it under Users).

Another is failure of the mail system to have setup the mailbox,
despite having sent a "your mail account has just been activated"
notice. One just has to wait a while and try again.