I had the same issue. When trying to pay the state filing fee , my pop-up box went blank. When I finally got an operator on customer service she suggested maximizing my screen resolution to 100%. It already was at 100%.
Talking with her, I figured out the problem - I had my (Nord) VPN on ! Even though it was connected to a local server , it was still blocking the TurboTax function here. I disconnected the VPN and the rest of my session sailed through. Just waiting for my confirmation emails & my $$$$.
