Hi! thanks for help. Unfortunately doesn't work. I have the same issue (2020 and 2021 versions installed). 
I tried web connect, also I tried to open the qbo file via menu (open file with - choose current 2020 .exe file) - nothing, the last i got is the menu "Import new transactions now" and then again error "QB is unable to verify the Financial Institution bla bla bla"
Any ideas please? (this is a new company and no transactions imported so far, bank is empty/no bank account (tried)).