Cannot open the user password file for reading

[MaZZie]

When a user goes to email account he get the next error Cannot open the user password file for reading

Where can i find that file?
And why is every user get this error?

I use Redhat 9.0

[jmstacey]

http://www.directadmin.com/forum/showthread.php?s=&threadid=802&highlight=can+not+open+password+file
http://www.directadmin.com/forum/showthread.php?s=&threadid=6627&highlight=can+not+open+password+file

There are more results as well, I used the following search term
"can not open password file"

[golfguy]

I found one more. I had a client rename his domain. I could not find him in a suspended state anywhere.

In SSH

cd /etc/virtual
ls

showed his domain as domain.com_off

I suspendend the account then un-suspended and it cleared the "reading password file" problem