To start with, try opening QuickBooks on a private window. There are instances that issues like this occurs when the system encounter cache traffic. You may use these keyboard shortcuts to open one:
Google Chrome: Ctrl + Shift + N
Mozilla Firefox: Ctrl + Shift + P
Microsoft Edge: Ctrl + Shift + P
Safari: Command + Shift + N
If it works, you can go back to a regular browser and clear its cache. Once a cache is piled up, it can cause some unexpected happenings on the opened pages like QuickBooks.
You can also switch to a different supported browser like Google Chrome, Mozilla Firefox, Safari, or Microsoft Edge.