We've received similar cases or reports about the issue logging into your QuickBooks Online account and getting the exact error. I know how this will impact your business operation, but rest assured that our product engineering team is working to solve this promptly.
For now, I recommend contacting our QuickBooks Support Team so they can add you to the list of affected users. This way, you'll receive email notifications about updates on the investigation. You can use the investigation number INV-107114 to expedite the process. Here's how you contact them:
Click on the Help (?) icon.
Select Assistant and enter Contact support in the chat field, and then click the Send icon.
You'll be asked about your concern, andyou'll need to enter and send it.
If you can't see any related topics to your issue on what they shared, select No, get me a human.