sims error code 300:ab0754d:e8c5fece

The game will let me create a sim or sims with custom content and save them to my Library. The second I put them in the actual game, it will refuse to save, and gives me this message: "The game failed to save. Error Code: 300:ab0754d:e8c5fece" 

This has been happening for months, and I am getting really sick of it. I can't enjoy my game properly anymore and it is infuriating.