@briannang6 It sounds like you only installed the base game, not Late Night or High-End Loft Stuff, the packs that come with the Starter Pack. The connection error you're seeing can be fixed, or it should just go away on its own if you install Late Night. Click the Sims 3 icon in Origin, then choose More > Expansion Packs (for LN) or Stuff Packs (for HELS), scroll to where each pack is listed, and click Download. If you don't see More, scroll down a bit—it's under the hours played number.
Once you've installed the packs, run the Super Patch (digital download version), as the launcher doesn't do a good job of patching on its own.
https://bluebellflora.com/sims-3-manual-super-patch-for-mac-1-67/
Then create an alias for Late Night in Applications\The Sims 3, alongside the alias for the base game:
https://bluebellflora.com/sims-3-packs-not-showing-as-installed/