Seems like there is one 's' too much in your link
Both links should work:
http://absolventensprechstunde.peterfaber.net
https://thdoodle.th-deg.de/FAGrtLpsgIcAfKPx
Both links should work:
http://absolventensprechstunde.peterfaber.net
https://thdoodle.th-deg.de/FAGrtLpsgIcAfKPx