Unable to start: The sims 4 is already running, error message.

Hi, 

firstly, I am on a MacBook Air (Retina, 13-inch, 2018) Version 10.15.3. 
I downloaded the Sims 4, played for a few hours the got an expansion pack. 

second time I wanted to access the game, it didn't open as I kept getting the "unable to start message - because it was "already running" (it wasn't thought). 
my next step was, restarting computer, closing all apps. 

I tried it again and it didn't work. 

then tried uninstalling the sims 4, at least 2 time and origin. 

the message kept coming up. 

im at a point where I think that this will not get fixed? 

thoughts and help please?