ns.anycastcluster.com has no MX records.
Question and response
Question
dig ns.anycastcluster.com. MX
Answer
The response has no answer records.
Authority
anycastcluster.com. 86400 SOA ns.nscluster.eu. hostmaster.nscluster.eu. 2026021901 7200 3600 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0