I don't remember why but I remember HardForum's 2FA being a pain in the ass so I disabled it
I remember it being a PITA too, I think with multiple browsers, one would time out and need a 2fa code and the other one would just be logged out. It got better (or I did) and now, everytime it prompts, I just grab my code from email and keep going. Might be worth trying again?