gemini.rrz.uni-koeln.de has no MX records.
Question and response
Question
dig gemini.rrz.uni-koeln.de. MX
Answer
The response has no answer records.
Authority
uni-koeln.de. 3600 SOA noc2.rrz.uni-koeln.de. hostmaster.uni-koeln.de. 2026030206 10800 3600 2419200 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0