Sehr spassige Sache, sind sogar dieselben Mailserver für beide Domains:
dig hispeed.ch mx
; <<>> DiG 9.18.39-0ubuntu0.24.04.3-Ubuntu <<>> hispeed.ch mx
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39778
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;hispeed.ch. IN MX
;; ANSWER SECTION:
hispeed.ch. 5 IN MX 10 mxin1-hispeed-ch.edge.unified.services.
hispeed.ch. 5 IN MX 10 mxin2-hispeed-ch.edge.unified.services.
;; Query time: 13 msec
;; SERVER: 127.0.0.53#53(127.0.0.53) (UDP)
;; WHEN: Thu Apr 09 16:07:25 CEST 2026
;; MSG SIZE rcvd: 126
dig swissonline.ch mx
; <<>> DiG 9.18.39-0ubuntu0.24.04.3-Ubuntu <<>> swissonline.ch mx
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 60311
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;swissonline.ch. IN MX
;; ANSWER SECTION:
swissonline.ch. 5 IN MX 10 mxin1-hispeed-ch.edge.unified.services.
swissonline.ch. 5 IN MX 10 mxin2-hispeed-ch.edge.unified.services.
;; Query time: 15 msec
;; SERVER: 127.0.0.53#53(127.0.0.53) (UDP)
;; WHEN: Thu Apr 09 16:07:32 CEST 2026
;; MSG SIZE rcvd: 130
Eventuell kann dir in diesem Fall auch abuse@sunrise.net helfen. Sende Ihnen gleich noch Datum und Uhrzeiten als Mails versucht wurden zu senden.