slb0.srs1.ntfo.org has no MX records.
Question and response
Question
dig slb0.srs1.ntfo.org. MX
Answer
The response has no answer records.
Authority
srs1.ntfo.org. 86400 SOA ntfo.org. postmaster.ntfo.org. 2026022400 86400 14400 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0