I had this problem yesterday when leveling up to 3. I sent in a ticket about it.
Today I messed around enough and got it to work.
Go back to your office.
Use the switch button on the right of the screen to choose a background.
Choose the 1st or 2nd. For whatever reason, the 3rd doesn't load.
Still waiting for a reply from Nutaku, but this has fixed the issue for now.
FYI , I tried to hover around the counter but nothing showed 😖
in the browser version you move your mouse on the figure that shows how many keys you have (top left), then a baloon tip comes up which shows you how many keys you earned today and how much the limit is