email forwarder error c forced address failure

If emails are not sending to one specific address/domain one one particular server, use the WHM Mail Troubleshooter to see if you get the failure below:

"cpanel virtual_aliases via virtual_aliases router forced address failure"

If you are getting this error, check the file /etc/localdomains and make sure the domain you are sending to is not in there. if it is, remove it.