I can’t charge my iPhone 6 on the Apple iPhone Lightning Dock
I have tried restarting and still doesn’t work, all other devices work on it
Have you tried to clean your device's charging port from dirt/debris/lint?
Have you tried all the steps provided in this support guide?
If your iPhone, iPad, or iPod touch won't charge - Apple Support
If the issue still persists, have your device inspected at your most convenient Apple Store or Authorized Service Provider: Apple - Find Locations - Location Selector
Regards
Giulio