451 Temporary local problem - please try later

[PCZero]

For just ONE of my 45 clients on this WHM/cPanel box (RHEL 4) I get the error message "451 Temporary local problem - please try later" when any email account attempts to send mail. Any idea whats happened and why its only affecting one account?

[cPanelDavidG]

For just ONE of my 45 clients on this WHM/cPanel box (RHEL 4) I get the error message "451 Temporary local problem - please try later" when any email account attempts to send mail. Any idea whats happened and why its only affecting one account?

I'd attempt to send mail from their account via webmail to ensure the account can send mail. If this works, then the issue may be related to IMAP/POP3 or the user's email client. If you can send mail from the webmail interface for that account, then I'd recommend checking the IMAP/POP3 logs at:

/var/log/maillog
/var/log/messages

[sv1]

have the same issue after moving accounts from another machine and installing "home directory backup". Anyone? Thanks.

[sv1]

See if this helps:
451 Temporary local problem - please try later