Deending on the age I would give her another try there could be some issues which may be on her part or maybe not.
Make sure she has access to food that meets her need and fresh water, if you have a watering system make sure the valve is working properly.
If both those needs are met, you can be dealing with either a bad or inexperienced mother, a mother that culled her babies because of milk production issues, the babies could have died and she was just cleaning up.
If you house the animal communally when birthing females may have fight over the babies killing them which is why I generally recommend to have individual birthing tubs until the babies are 5 to 7 days old.