United Domains: forward to https

so a friend of mine has this website setup in united domains and he set up some forwarding which works in most cases like

http://something.de => forwards to https://www.something.de/ OK

OR

https://www.something.de => forwards to https://www.something.de/ OK

BUT

http://www.something.de => stays http://www.freeinsurancedata.de/ and doesn't forward to https .

Does somebody now how to force https in united domains or a different way to fix it?