Thanks for letting us know. I'm here to help and provide some insights about bank accounts are not syncing with QuickBooks Online (QBO).
Are you trying to connect PayPal app to QBO? If so, we've recently received reports that this is a known issue in QBO, our engineers are currently investigating and working on an immediate fix. I suggest reaching out to our Customer Care Team to add your account to the list of affected users. This way, you'll be notified of any updates on the progress of the investigation via email.