Game no longer saves

 I have recently purchased The Sims 4 the other day via Steam and have enjoyed it so far. However, within my first 3 days of playing, I have now been struck with an Error 21 message that pops up whenever I try to save the game. It happens when I try both the “Save” and “Save As” options, and also if I click “Save and Exit to World.”

I tried creating a new game with a new family, and all was well until it got to confirming the family. Then I was stuck on a permanent loading screen, which let me click off it, but there was no way of continuing to the world.

I do not have any custom content/mods. The only expansion packs I have are Cats & Dogs, My First Pet Stuff, Parenthood, and the base game.

It has now come to the point where I can no longer play, which is really disappointing, as I haven’t even been able to play for more than a couple of hours because it’s just unplayable now. I am not signed into my OneDrive and have no antivirus apps running. I’ve tried looking for help online, and still nothing seems to be working.

I know its a different game entirley but i never had these problems with Sims 3 or any other game when it comes to saving.

Does anyone have any advice?