Welcome and thank you for joining the thread, @Bksparks.
Allow me to help share information about Banking Error 377.
As mentioned by our colleague RenjolynC, this error means that QuickBooks is unable to download transactions from your account because the connection type with your bank needs to be updated.
To resolve the error you may need to connect your bank directly.
- Click on Banking at the left pane.
- Select Banking.
- Click Update beside Add account.

For additional reference, you may check these articles:
Stay in touch if you have any other banking questions by adding a comment below, I'm always here to help. Have a wonderful day!