Imported account from different server, created a new email address, can't log in

I'm having an issue getting a newly migrated account's non-imported email account logged into webmail (or at all).

I'm able to login to webmail, but when I select, Horde, RoundCube or SquirrelMail, I get "Login Failed" -- won't let me log in.

I can, however, log in using an imported email account.

I've ran

Code:

/scripts/whoowns domain.com

and it looks great.

I've also ran:

Code:

tail -fn0 /var/cpanel/roundcube/log/errors

and get the following line:

Code:

 IMAP Error: Login failed for [EMAIL ADDRESS IN QUESTION] from [SERVER MAIN IP - not IP assigned to account]. AUTHENTICATE PLAIN: Authentication failed. in /usr/local/cpanel/base/3rdparty/roundcube/program/lib/Roundcube/rcube_imap.php on line 184 (POST /cpsess380702541/3rdparty/roundcube/index.php?_task=login&_action=login)

Any Idea? I'm at a loss, and rather frustrated that I can't figure this out.

Thanks!

 

As an update, I've set: "Mail authentication via domain owner password" to True in Server Settings > Tweak Settings > Mail and attempted to log in using that account - still the same issue.

 

Somehow, everything seems to be working now. The only thing that changed since my last post was time...