Did you buy this bike new or used?

If new, have you taken it back for it's initial (usually free) tune up? ALL, new bikes need an initial break-in period. The cables when new will stretch a bit and the resulting slack needs to be removed and the shifters readjusted for smoother shifting. Same for the brakes.

Is the chain coming off at the cranks to the inside? Again, the front shifter may be out of adjustment and can be overshifting to the inside.

Also, your limit stop is probably not correctly set and is allowing for the front derailleur to be too far inward, causing the chain to come off.

Hard to tell without looking/touching the bike!

If used, did you recently replace the chain? If so, did you replace the cassette as well? What about the chainrings?

The reason I ask is, if your chain was overly-worn, you could have damaged the teeth on the cassette and chainrings as these wear out as well. If your teeth have sharp point as opposed to a flat spot near the top, they worn out and are causing some problems, but not "Chain-Drop" usually. If this is a problem, it's usually chain skip!

Once again, hard to tell.

L8R