Yes, extending your course is possible if it hasn't been expired for too long, ideally within a few weeks, since regulations are subject to change. You might have the option to enable autorenewal or pay for an extension. Generally, upon your course expiration, you'll be prompted with the option to pay for an extension.
In cases where your course is deemed permanently expired, you will encounter a “registration expired” message upon login, indicating the need to set up a new account.