The app uses  the Google Play Licensing system to verify that the app was purchased through the store. This feature allows the app to ensure that is is a paid version and not an illegal copy.

The Anti-piracy features of the app ensures that only valid users can use the app and that illegal copies aren't able to run. This also includes pirated versions of the app that are sometimes found on "free" app stores, which are known distribution channels for pirated software. Read more about it here.

But I have paid for the app!
If you have indeed purchased the app and own a legit version and the app still doesn't start as it should on your device, you should try the following methods of fixing the error:

Don't move the app installation
Some apps enables you to move the install location of the app, which may cause the Google Play License Verification system to identify the app as installed from a 3rd party/illegal app store.

Check the Google Play account
When the app is installed, ensure that you're using the same Google account in Google Play, that you used when you purchased the app. The app purchase is connected to that specific account and won't run unless you're logged in with that account when running the app:
https://support.google.com/googleplay/answer/6178908

1. Open the Google Play Store app .
2. Touch the Menu icon . You'll see the account you're signed in to at the top of the menu.
3. If you want to select a different account, touch the dropdown arrow .

Sync the Google account Data
Assuming that your phone is connected to active internet (Wi-Fi or 3G/4G Internet connection), and then follow the below steps:

1. Close down the app entirely.
2. Go to your phone Settings and tap on the Account / Account and Sync option (depending on which Android version you have installed on your device).
3. Tap the account that is connected with your device and Play Store.
4. Enable the option “Sync App Data” if it isn’t enabled / or tap Sync Now in the top/right menu.

Reset the Google Play store cache
Assuming (again) that your phone is connected to active internet (Wi-Fi or 3G/4G Internet connection), and then follow the below steps:

1. Uninstall the app.
2. In the Settings, go to Applications.
3. Now go to Manage Applications.
4. Locate the Google Play Store/ Download Manager app and select it.
5. Now press Clear Data and then Clear Cache.
6. Then install the app again from Google Play.

Contact the Google Play Support
If the above doesn't work, there may be something wrong with the Google Play Verification system. As with most Internet services, temporary disruptions sadly sometimes occur. Try to start the app again in a couple of hours, and if it still doesn't work, contact the Google Play support and tell them about your problem:

https://support.google.com/googleplay/answer/6179357

Ask for a refund
If the problem persists or if you don't want to try any of the above methods, we will of course refund your purchase in full, since you should not pay for anything that you can't use.

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