It wont let me play the game play

For the past couple of months, my game hasn't been letting play the actual game play. I can still build, still update, still create sims, and none of my progress has been deleted. But when I try to play the sim I want, it loads for a few seconds to a minute before kicking me back into Manage Worlds. It's been quite annoying to deal with. I've had my computer updated as well so i know it's not that. I have mods as well but I've tried playing with them off and it still doesn't work.