When you fail to make payments for your car insurance then it will eventually become cancelled however the auto insurance company will notify you by mail before they cancel your insurance policy with them due to non payment.
Then you have a certain amount of time to get your car insurance paid for before they cancel it.
Once they cancel your auto insurance due to non payment your insurance company will no longer cover your vehicle.
So you'd be driving without auto insurance which can get you a ticket, and possibly have your vehicle impounded as a result.