You can follow some of the recommended troubleshooting steps below, Calvds.
If you're using QBO Desktop App, all you have to do us is to clear the cache. You can do this by following the steps below:
If this won't help fix the problem, you can try uninstalling and reinstalling the program.
Here's how to uninstall:
Here's how to reinstall:
However, if you're using the browser when logging in to QuickBooks, you can try using an incognito window. If it works fine, go back to your regular browser and clear the cache. You can also use other compatible browsers with QuickBooks.
Give me an update by replying to this thread on how these steps go. Have a good one.