_web.relay.tmt.de has no CNAME records.
Question and response
Question
dig _web.relay.tmt.de. NS
Answer
The response has no answer records.
Authority
tmt.de. 526 SOA ns0.tmt.de. hostmaster.ns0.tmt.de. 2025101052 28800 7200 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0