Can you screenshot what you mean, not sure where that is.
MX records can point to any name as long it has a A record.
Suggested record are just that, a suggestion.
Ok, so the servers hostname (not the vrtualserver) is not taking.
Templates only work on new created virtualserver (I think), so you tested on a new virtual server.
Yes this is setup for newly created virtual servers. The template adds all rules and additional records no problem, accept the hostname entered for the MX record. I believe this worked in the past on an old server that’s long gone but doesn’t work here on the new server.