Learn how to fix bank error 106 in QuickBooks Online.
Banking error 106 means QuickBooks can't find your account on your bank or financial institution's website. This usually happens when the account is closed.
For a better experience, open this article in QuickBooks. Launch side-by-side view 
If you closed your bank or financial institution account and need to disconnect, here's how. Follow the steps to disconnect, remove, or delete a bank or credit card account from the Downloaded Transactions page.
If you need to, you can reconnect your account. Just make sure it’s not already connected on your chart of accounts.