Here are the permissions for each level of the /home/username/etc per one of my own accounts:
/home/user/etc permissions
Code:
drwxr-x--- 6 user mail 4.0K Jan 28 15:27 etc
/home/user/etc/domain.com permissions
Code:
drwxr-x--- 5 user mail 4.0K Jul 9 12:50 domain.com
/home/user/etc/domain.com permissions inside the folder
Code:
drwx--x--x 4 user user 4.0K Apr 10 15:52 admin
drwx--x--x 3 user user 4.0K Apr 10 15:52 cpacct
-rw-r--r-- 1 user mail 152 Feb 24 13:23 passwd
-rw-r--r-- 1 user user 1.9K Feb 24 13:23 passwd,v
drwxr-x--- 2 user mail 4.0K Feb 24 13:24 @pwcache
-rw-r--r-- 1 user user 33 Feb 24 13:23 quota
-rw-r--r-- 1 user user 387 Feb 24 13:23 quota,v
-rw-r----- 1 user mail 107 Apr 10 16:00 shadow
-rw-r----- 1 user user 2.0K Feb 24 13:23 shadow,v
Please note the ownership permissions really matter quite a bit. The /home/user/etc, /home/user/etc/domain.com and /home/user/etc/domain.com/passwd, @pwcache and shadow all have user:mail permissions not user:user permissions.
If your permissions and ownership are correct for each of these, then also cat the /home/user/etc/domain.com/passwd file to see if the accounts are listed there. Sometimes they are missing. If they are indeed missing, then you will have to remove and re-create the accounts to restore the data. You can copy the /home/user/mail/domain.com/emailuser folder to a backup before removing the account, then restore the contents of that folder so that you don't lose the data, though.