Your subscription may have lapsed. If you are currently subscribed, you should open TriPeaks and tap Settings, then tap Remove Ads. Then tap Restore subscription.

If your subscription has expired, you must renew your subscription to keep using TriPeaks Premium. To do so, open TriPeaks, tap on Settings, then tap on Remove Ads. Choose your term and proceed with your purchase. Your new term will start immediately.

You can check your expiration date by following the steps in the article for How do I stop or change my subscription.