Your subscription may have lapsed. If you are currently subscribed, you should open ColorArt and tap on Settings, then tap Restore.
If your subscription has expired, you must renew your subscription to keep using ColorArt Deluxe. To do so, open ColorArt, tap on Settings, then tap on Get or Renew Deluxe. Choose your term and proceed with your purchase. Your new term will start immediately.
You can check your expiration date by following the steps How do I stop or change my subscription?