Intuit

How to resolve Error 377 in QuickBooks Online

Banking Error 377 usually means QuickBooks is unable to download transactions for this account because we need to update the connection type with your Financial Institution (FI). Until the new Direct Connection is established, no transactions will be downloaded for this account.

To resolve this error, please follow the steps from the Update Now link from the banner on the Banking page.

The banner on the Banking page is shown here:

Let's fix this bank connection.  
The old connection is gone. Reconnect now with the new faster, more reliable one and get back on track. (377)
Update Now

For more details on why we are changing the way we are connecting to your bank, please checkout this article.