zimbra.ukservers.com has no MX records.
Question and response
Question
dig zimbra.ukservers.com. MX
Answer
The response has no answer records.
Authority
ukservers.com. 60 SOA ns1.ukservers.com. networks.ukservers.com. 2026021900 1800 7200 1814400 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0