For some reason one of my domains dropped its MX record and users cannot receive email. The record is the default one in the control panel. I opened a ticket but have not heard from anyone.
you can just log in the Hsphere cp for the domain which you have the missing MX record and go to DNS , there you will find Restore Default MX records . This will give you the MX records.
Currently we have some issue with Ticketing system, you can just send a mail at techsupport \@/ jodohost \./ com [ remove the / and spaces here ]
You can click on "Restore default MX records" and this will remove all conflicting DNS records.
Btw, do you have a ticket in yet about this issue?
Maybe we can help you better there when we have details about this specific issue.