Please try rebooting the app

1. Open the App Store on your device and check that you are logged in to the account that purchased the app, if you are not, please log in.

2. Force close the app

- On an iPhone X or later or an iPad with iOS 12, from the Home screen, swipe up from the bottom of the screen and pause slightly in the middle of the screen. On an iPhone 8 or earlier, double-click the Home button to show your most recently used apps

- Swipe right or left to find the app that you want to close.  

- Swipe up on the app's preview to close the app. 

3. Reopen the app, it should be unlocked.