In a cPanel server if you find the error like this

Go to the path below :-

# /var/cpanel/email_send_limits

After go to the path, you can see the defer file related to the domain. If you found it you can directly remove the file.

After that restart the exim.

# /etc/init.d/exim restart

If that file is not found please check for spamming. Then increase the value in modify account and mail tweak settings.

• cPanel