Email account password change not being accepted by login

Are you making a password change in cpanel for an email account but its not being accepted at login? There are generally two causes for this.

etc/shadow

Check $HOME/etc/domain.com/shadow. A common cause is a missing :

Wrong

root@server1 [/home/user/etc/domain.com]# cat shadow 
info:$1$f007E75t$O.vlh6h2veFgtxkGdRddY0
aida:$1$lGMZ0ivm$37Mo5YUtIU6av7BAKAj5K0

Correct

root@server1 [/home/user/etc/domain.com]# cat shadow 
info:$1$f007E75t$O.vlh6h2veFgtxkGdRddY0:
aida:$1$lGMZ0ivm$37Mo5YUtIU6av7BAKAj5K0:

Notice the Correct one ends with :

There was a previous cpanel bug that removed this line.

Unsuspend account

There have been cases where an account did not fully suspend. Re-unsuspend the account in WHM or with /scripts/unsuspendacct