In some cases you will need to start The Sims 4 in Origin mode.For example if the game is set to run at a resolution/refresh rate that is unsupported by your monitor, you can't get into the game to revert it back. In some cases, when the game is initally setting up, the game can misread the PC's display information, which can lead to the same situation.
Fortunately the fix/workaround for this is quite simple:
Open up the details page for The Sims 4 and you should see the Game Properties button. To get to the details page click the "i" icon
Then enter the "-w" line into the box that appears.
Start the game and hopefully this will help with the issue at hand.