Error:
When you try to send mails from any email client using cPanel, you may see the following error flashed
SMTP Error (451): Failed to set sender "test@example.com" (Temporary local problem - please try later)
Solution:
Let you are trying to send mail from "test1@yourdomain.com" to "test@example.com"
If "test1@yourdomain.com" is using local mail server, the command given below must display "yourdomain.com" as result.
# cat /etc/localdomains | grep yourdomain.com
If the output is null, add an entry for "yourdomain.com" in /etc/localdomains.
Also remove the entry of "yourdomain.com" in /etc/remotedomains if there exists one.
