There are a few different causes to learn about, but the most common are as follows.
One: Buildup of food waste – There is a lot of different food items that can be put in a garbage disposal to dispose of it, but there are also a few items that should never be placed in it. These things include potato peels, egg shells and coffee grounds.

Clogged Garbage Disposal
These are the types of items that with time will cause a buildup of food waste that is left in your pipes and when there is too much of it, your garbage disposal will clog. Always throw these items in the trash can and never down the disposal because this is the best way to prevent a clog.
Also, be sure you never put oil or fat down the garbage disposal because this also causes a buildup that will quickly lead to a clogged disposal. Dispose of oil and fat in other ways, but not down the disposal, unless you like unclogging it.
Two: Not using enough water – Each time that you use your garbage disposal you have to make sure that you are always using enough water to help all of the food particles go down the drain the through the pipes effectively. Without enough water being used, you can count on at least some of the food to remain behind in the pipes and each time you use it this will cause a buildup and eventually a clogged disposal.
Be sure to use water before you turn the disposal on, during the process and for about 20 seconds after you turn it off to help you ensure that all food particles are washed away.