The licensing error you're getting is on Google's end, but there's a few things you can try to get the game going. Stay connected to the most stable internet connection you have access to (WiFi, preferably) while trying each fix:
- Make sure you have the correct date and time, and latest updates for your device. After that leave the game open with the error message displayed. The game should be rechecking the license then, so it may just need 5-10 minutes.
If the error still appears after that, launch the game directly from the Google Play Store app following these steps:
- In the applications screen find and select the "Google Play Store" app.
- Search for Bloons TD 5 and select it.
- At the top the screen hit the "Open" button located next to "Uninstall". The game should now connect to the store finishing the licensing process. This can take about ~1 minute, and interrupting the process could cause more sever problems.
- If that fails, uninstall Bloons TD 5 and clear the cache from the Google Play Store & Download Manager apps following the steps below.
Go to your device Settings.
In settings, go to "Applications".
Now go to "Manage Applications".
Locate the "Google Play Store/ Download Manager" app and select it.
Now press "Clear Data" and then "Clear Cache"
Then re-download Bloons TD 5 using the most stable connection you have.
Important: Reinstalling the game delete your progress, so if you've played a bit already, you might want to hold off doing this step. The license is rechecked by Google regularly (every 24 hours) so if you have progress you don't want to lose, let the game sit for a day and come back to it