I am unable to save my game. Error code 0!

Hi, error 0 means you've hit the limit for save data so it doesn't let you save anymore. Consoles only have a certain amount of save space on the system reserved for each game. I had the same thing while playing Fallout 4, that game autosaves after everything you do and they take up all the save space. Just means you need to delete some things to free up space like households, Townie NPC's (especially if you have sim count set to anything higher than 80 and alot of gallery content) save files you don't mind deleting etc, also going into old saves and getting rid of all the things in their personal and household inventories helps.