ns2.myfritz.net has no MX records.
Question and response
Question
dig ns2.myfritz.net. MX
Answer
The response has no answer records.
Authority
myfritz.net. 1 SOA ns2.myfritz.net. admin.avm.de. 3504396483 20 20 86400 1
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0