mx.xen17.node6514.gplhost.com has no CNAME records.
Question and response
Question
dig mx.xen17.node6514.gplhost.com. NS
Answer
The response has no answer records.
Authority
gplhost.com. 1692 SOA gemma.ns.cloudflare.com. dns.cloudflare.com. 2396249041 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0