Origin won't launch Sims 4?

Hey!

So I haven't uninstalled Sims 4 from my account but Origin keeps telling me I must download the game, however, when I tried to do so in an attempt to fix the problem my Mac keeps giving me the following message: There is no application set to open the URL steam://run/1222670. Search the App Store for an application that can open this document, or choose an existing application on your computer.

I tried redownloading Origin but it didn't make a difference, I'm super confused because the day before the game ran perfectly. Thanks for any advice!