It's important to pay your monthly premium in full to your health insurance company by the due date. Your coverage could end if you fall behind on payments. But before your health insurance company can end your coverage, you have a short period of time to pay called a "grace period."
The health insurance grace period is 90 days.
The grace period starts the first month you fail to pay, even if you make payments for following months. If your health insurance company ends your coverage because you didn't pay all outstanding premium payments in full by the end of your grace period, you have the right to appeal if you believe it was wrongly terminated.