Swedish internet provider Bahnhof seems to be blocking outgoing SMTP connections. wtf?

14:32:10.650068 IP trias.wlankarow.de.51899 > wlankarow.de.smtp: Flags [S], seq 2488790664, win 65535, options [mss 1460,nop,wscale 1,nop,nop,TS val 149635633 ecr 0,sackOK,eol], length 0
14:32:10.653313 IP utsikt-student-spiderpig-gw.bahnhof.net > trias.wlankarow.de: ICMP host wlankarow.de unreachable – admin prohibited filter, length 36