I just checked with TCPView:
there are connections ranging from ports 3670 to 4044.
but the default ports for unreal engine games have been 7777-7779 in the past.
maybe you can try those or on first try checking with exposed host settings to be sure.
(but please don't keep it for the sake of your system security)
if this helps and none of the ports i listed are helping, maybe asking jace on twitter will give the answer.