Do not uninstall the app. Check your internet connection and try to activate later.
If the activation is still unsuccessful, follow the instructions below:
Copy/paste the Transaction ID into the Order Number field in the form below. It will be in the format: GPA.XXXX-XXXX-XXXX-XXXXX. If this does not work, try pasting the Transaction ID without the GPA. into the Order Number field.
Type your Google Account Email (for the account you used to purchase) into the corresponding field below.
Type the two words you see in the picture below.
Click Submit to activate your application.
Check your Google Account Email to find your ESET-issued License Key.
If you are still not able to activate your application, you are eligible for a full refund within 30 days of your initial purchase. To request a refund, visit your Google payments center (you will need to log in under the same account you used to purchase your application).