Have some of the settings on your Photoshop changed out of nowhere? If yes, then you can restore the preferences settings to default on Your photoshop so that everything is reverted back.

We personally had the issue of using a paint tool for using the background color and unfortunately could not fix it at all. But by resetting the Photoshop we were able to make it work all again.

We really hope you will also be resolve any of your photoshop issues simply by resetting it. Thank you.