I went through these steps. Something I was not able to do was switch from wi-fi to an ethernet cable; my computer is not in the right room for that. It's just not practical.
In particular, I tried updating Origin by running the platform as an admin, and clearing my DNS cache using ipconfig. The other things I'd already tried. No change whatsoever.
As for opening ports--is that step relevant to this game? I went to that page and it listed many games that needed specific ports opened, but It Takes Two was not one of those games.
I see someone "accepted this answer as a solution" -- can they share what they did that worked?