Let's access your account via an incognito window to fix this error. This way, we'll be able to know if this has something to do with the browser you're using or not. I'll guide you how.
Once done, check if you're still getting the error message.
If you don't see the error, go back to your regular browser and clear your browser's cache.
Give us a call if you're still experiencing the same results, so we can check your account and investigate further.
Here's the link to reach us: Contact the QuickBooks Online Customer Support team.
Feel free to check our site in case you need future reference about: Income and expenses.
Drop a comment below if you have questions. I'd be sure to reply as soon as I can.