Let me help connect your bank accounts to QuickBooks.
Currently, there's no reported issue about bank connections in QuickBooks. To resolve your concern, let's perform the basic troubleshooting by using a private browser to check if the issue is browser related. Please follow the keyboard shortcuts below:
For Chrome, press Ctrl + Shift + N.
For Internet Explorer or Firefox, press Ctrl+Shift+P.
For Safari, hold down Command+Shift+N.
After that, try logging in to your QuickBooks Online account then connect to your bank accounts. If it works using the private browser, go back to your regular browser and clear the cache and cookies to remove temporary internet files.
On the other hand, you can also update your bank register manually by pressing the Update button up to two to three times to see if all transactions are uploaded to QBO. Here's how:
Go to Banking.
If you only want to update some of your accounts, select to clear the unwanted accounts.
Click the Update button in the upper right.
If prompted, enter your Multi-Factor Authentication (MFA) credentials (must be done within 2 minutes of box appearing) and then select Continue Update.
If you changed your bank account's username or password recently on your bank's website, you'll need to update the credentials in QuickBooks Online to reflect the change. Please refer to this article for your reference: How to Update your Bank Account Sign-in Information.
If you've tried all the steps above and your still unable to connect your bank, you can manually bring in transactions using WebConnect. Let’s download the transactions from your bank, then log in to QBO and upload the WebConnect file:
Login to your bank website and select the date range of transactions you want.
Select an approved file type (CSV, OFX, QFX, and QBO) to convert transaction data to.
Save the transaction file to your computer.
Login to QuickBooks Online.
Go the Banking tab and choose Upload.
Under Browse, select your transaction file.
Click Yes on the notification asking if you want to import now.
Hit Let’s go when you get the Import Completed window.
You will be routed to the Downloaded Transactions window where the imported transactions will appear under the For Review tab.