mx03.rrz.uni-hamburg.de has no MX records.
Question and response
Question
dig mx03.rrz.uni-hamburg.de. MX
Answer
The response has no answer records.
Authority
uni-hamburg.de. 7200 SOA ns.rrz.uni-hamburg.de. netgroup.rrz.uni-hamburg.de. 2026030312 10800 3600 604800 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0