mail.a4a.de has no MX records.
Question and response
Question
dig mail.a4a.de. MX
Answer
The response has no answer records.
Authority
a4a.de. 300 SOA get.desec.io. get.desec.io. 2025106031 86400 3600 2419200 3600
Additional
. 0 OPT ; payload 1400, xrcode 0, version 0, flags 0