@Looneybin1978 Go to ea.com, sign in, click your profile picture and then Account Settings, click Connections, and see whether the Steam account that owns Sims 4 is connected. If it is, make sure you sign into Origin with the same account (use the same email address) that you used on ea.com.
If your Steam account is connected to a different Origin account, you'll need to sign into that account instead in order to play Sims 4.
If your Steam and Origin accounts are in fact connected, please run both Steam and Origin as an admin: right-click on each one's shortcut and select "Run as administrator." Then try to play.
If this doesn't work either, please post a screenshot of the error you get.