mkucharz commented :
@danielmai https was left after testing dgraph-js-http… I’ve updated original question (because I still had a problem even without https).
Anyway, your @gorjuspixels and @danielmai responses were very helpful.
It turned out that the problem was in common name of the certificate… I forgot to generate it with additional host names, more info here:
https://docs.dgraph.io/deploy#file-naming-conventions
Leaving this message mainly for other people lost in similar place 