The first step to trouble shooting an email problem if you are using our webmail server is to check the MX (mail exchange records) DNS to make sure it's pointing to the our server correctly. One easy tool used to check your MX records is to go to a website called leafdns.com. Leafdns is a site used to pull the active DNS for any domain thats live.
As you can see in the example above, the MX records are still pointing to Google. If the DNS is not pointing to our email server then you are able to update the MX record in the cPanel under the bar that says Domains and click on the icon that says Zone Editor.
Once on the page that says Zone Editor you'll be able to see the domains that you have hosted with us. To the right of each domain the option Manage will allow you to make changes to that specific domain DNS record.
Now on the Manage page, if there are existing MX records such as the Google records you can remove the old information and enter the correct ones pertaining to your account. To make the necessary changes, the Actions column will have a EDIT button. If you do not know what your MX Records should be, by default it's always "domain.tld" (your domain name). Once updated, click on the SAVE RECORD button to make sure that your changes are saved. After updating the MX record, Also double check that the CNAME record has been updated as well.
Since changes in the DNS Zone have taken place, they will have to propagate which could take up to 4 hours, but typically will resolve sooner. Once the propagation has finished your email should be back running and LeafDNS will reflect the changes made.