Do you have to be a member to use RuneScape Classic

Yes, awhile back, Jagex made the RuneScape classic available for only members. This was because it was used to cause trouble by free players, and Jagex didn't want to work on focusing on the old game. But not just any member can use it, you have to have had an active account from a few years ago before they changed the game. And you have to log in every six months or you lose the ability to play, sadly.