My customers can’t access their POP3 accounts with their e-mail clients. They get this error: “There was a problem logging onto your mail server. Your username or password was rejected. Server response: “ERR aack, child crash”.

Your open-smtp file got corrupted. In SMTP-after-POP, this file is responsible for opening SMTP relay for specific IP addresses. When user conects by POP3, his IP address is saved in that file. Once the user tries to send anything, this file is checked for the users IP address.

To fix it, execute the following commands:

cd /hsphere/local/var/vpopmail/etc
cat /dev/null > open-smtp
/hsphere/shared/bin/tcprules tcp.smtp.cdb tcp.smtp.tmp < tcp.smtp
chown vpopmail:vchkpw *