Do you have any mods in your game? Try removing them and see if it works. Otherwise, try backing up and resetting your files.
There are instructions for it on both Mac and PC here:
https://help.ea.com/en-sg/help/the-sims/the-sims-4/backing-up-and-resetting-the-sims-4/
My games were not saving- if I was lucky, at least the Sims that I made would save as a household, but all progress was lost. After backing up and resetting my files, will this ensure that I can now save regularly? How do I know if I need to take further steps? The game progress of that household was not recovered after backing up and resetting- should a recovery have happened if the backup and reset was effective?
