I'm happy to help you fix your American Express business card connection, but I need you to answer a few questions.
Are you getting any specific error message(s)?
Can you provide a screenshot?
By providing the specific error message and screenshot, I can determine what's happening with QuickBooks and AMEX's connection. In the meantime, I recommend opening QuickBooks in a private window and reconnecting the account there. This will prevent the web page from collecting your browsing history and allow a new connection to our program.
If you're able to connect your American Express account through the private window, you'll want to clear your cache and cookies in the regular browser to prevent this issue from happening in the future.
I'll keep an eye out for your response. Take care.