This is caused by failure in checking Play Store license. RaceChrono checks the license periodically, so if you hit this error, there’s a few things you need to check:

1) Make sure your device has internet connection. It does not need the connection for every start, but if you keep running the app without connection, you will eventually hit this error.

2) Make sure you’re logged with your Google account, and it is the same that you made your RaceChrono app purchase. Open the Play Store app; the account name is shown on the top of the menu.

3) Make sure your phone time, date and time zone is correct. The verification will fail if it thinks the license has already expired.