The situation is quite simple to describe - Picard 2.3.1 doesnt work with proxy settings enabled, while Picard 2.1.3 works ok (with the same settings).

It happens on my work machine where internet is organized through proxy (like ip:port) and unfortunately i cannot say anything more about network, since its managed by other people.

I also tried to run it through proxifier, but with zero effect - proxifier even doesnt show any network connections attempts from picard side, while 2.1.3 is working normally through proxifier.