Please verify subscription status through the Purchase History section:

  1. Open the Settings app. 
  2. Tap your name, then tap Media & Purchases. You might be asked to sign in.
  3. Tap Purchase History.
  4. If you see 2ndLine subscription under the Pending section, it means that the amount may be debited from your account but is not yet settled with Apple.

In such a case, Apple does not confirm a successful subscription to the app. You can read more about this from Apple's site here.

Once Apple confirms a successful subscription, the app will work fine.

In other words, if you see the active subscription under a recent date within the Purchase History section, but just in case the app is still not working for you, please contact us with details so we can provide you support.