mail.hessling.online has no MX records.
Question and response
Question
dig mail.hessling.online. MX
Answer
The response has no answer records.
Authority
hessling.online. 600 SOA ns01.uptime.de. hostmaster.uptime.de. 2025102900 10000 1800 3024000 40000
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0