QuickBooks is an accounting software that is used by businesses of all sizes to manage their financial data. However, like any other software, QuickBooks is not immune to errors. One such error is QuickBooks Banking Error 108, which is a banking error that can prevent you from accessing your banking information within the software. QuickBooks Error 108 occurs when there is an issue with the login credentials that you have used to connect your bank account with QuickBooks. It could also happen if your bank account has been closed or if there is some maintenance going on with your bank's website. If you encounter this error, you will see the following message on your screen: “Oops! We’re sorry, but we can’t update your account. Please try updating again later. (108)”
Source: https://www.zupyak.com/p/3632188/t/how-to-resolve-quickbooks-bank-error-code-108