Occasionally this happens on iTunes created accounts, so we've implemented an easy fix right into the app for you. Here's what to do:
Please go to the account settings on your iPhone (or iPad) app by clicking the button with the three parallel bars (or a left swipe).
Please find "already Subscribed with your iTunes account?"
Click the "Restore Your Subscription" link.
After clicking that link your account should be set up properly to use across all devices and computers.