Let's perform some browser troubleshooting steps to isolate the issue. To start, access your QuickBooks Online (QBO) company using a private browser. Private mode prevents storing cache and cookies that might cause problems when running websites.
Here are the shortcut keys you can use:
Google Chrome: press Ctrl + Shift + N
Mozilla Firefox and Microsoft Edge: press Ctrl + Shift + P
If this works, go back to your regular browser and clear the cache. This will remove the stored cache or cookies to refresh your browser. If the same thing happens, use another supported browser. It could be that the one you're currently using has a temporary issue with QuickBooks.
If the issue persists after the troubleshooting steps above, I suggest reaching out to our technical support team. This way, they can further investigate the cause of this unexpected problem and review your account set-up.