There might be a connectivity issue involved with your device and our servers. Here are some things you can try to help resolve:
Try registering on both your mobile carrier's network and a Wi-Fi connection. If the problem persists, try moving to a different Wi-Fi network
Force close Tango, then launch and try to register again
Uninstall and reinstall Tango and try to register again
If you've received an error message stating that "Your device has been blocked", please click HERE for more information.