Some users experience charging issues with their Gravitas and a common culprit with charging issues is actually not the Gravitas itself, but a build up of lint in the lightning port of your phone. Try carefully cleaning that out and see if it helps. We have experienced this issue first-hand and pulled extraordinary amounts of lint from some of our phones here at Henge Docks headquarters.
If cleaning the phone's Lightning port does not resolve the issue you can also clean the connector on the Gravitas itself. Using a cotton swab (cotton bud) soaked in isopropyl alcohol, gently rub both sides of the connector and wait let it dry for about 20 minutes.
If charging is still not working there are a few more things to check.
Feel free to submit a support ticket if you are still having trouble and we will do our best to help you resolve your charging issue!