most likely, you have the Location Services Off for your phone or Honk. To fix it, please follow this instructions:
1. Go to Home > Settings > Privacy
(for iOS versions earlier than 5, you may go instead Settings->Location Services)
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2. Go to Privacy > Location Services
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3. Make sure to turn it ON for both Location Services and for Honk in the list!
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4. If this didn't solve the problem, please contact us! We will do our best to help you.