I'm having the exact same problem, had it in Q2, and now for Q3 again.

Rejected payments despite having a current password and Pin for EFPTS. 

I can log in via one browser (Chrome) but not in another (Edge) in case that has some impact on the situation.  Last resort I will pay via their system, not thru QB if necessary. 

Pretty frustrated. Can you help?
Currently on a long hold for chat assistance.