I was having the same problem with AMEX continually asking for password - found this solution = 

I opened bank feeds in classic mode

Opened bank feeds

Held the CTRL button down while working in the bank feed window

Selected just one of the AMEX transactions and clicked delete

Had a window pop up to confirm - select yes

Selected the other AMEX transaction and did the same

Once cleared, I was able to deactivate the online bank feed services for AMEX

I went to the amex account and downloaded the qbo files - imported into the file with no problem.

When I tried to go back to auto download, the system locked up and wouldn't let me set it up. Still able to import the downloaded file though.