Originally Posted by
LaziestRaccoon
separately, so I assume it is not regarded as a connection

Correct; that’s why it’s not giving you an A-C option. It’s also possible that you’re in different fare classes on the two legs, which would add an extra complication.
Originally Posted by
LaziestRaccoon
What I see is it is illegal connection but the website and the app regard them as a legal connection so sth is messed up.
Because once you make it a sub-4 hour connection, it does treat it as a connection, and you haven’t boarded the first leg yet.