Many iPhone 6/6s/7 users who tried to charge their iPhone with fake cable are facing issue that they cannot charge the iPhone with any other charger. Even the iPhone is not chargeable with genuine original iPhone Charger. iPhone 6s used to work with it's original cable before but due to this cable got broken and user opted for a fake cable, iPhone currently charges with fake cables only, but doesn't recognize any official ones. Also it doesn't work with lightning headphones from Iphone 7, but iPad mini see the headphones without any issues the same like iphone 7 does.
To fix the iPhone 6s/7 not charging with original cable, user tried to Factory reset the iPhone and it worked with the Apple charger for about a day then it stopped. Now then tries with fake charger and it worked again. The fake charger sometimes give very poor battery life as it drain too fast. This is very annoying issue for the customer as fake charger gives many issues like poor battery life, iPhone heating up etc. Even the phones I not connecting to iTunes now.
why does my phone only charge with one charger :
This does not seem to be software bug as seems to be hardware failure due to some reason. Many customer tried cleaning the port, blowing it out , hard restart, factory reset, replaced the charge port but unfortunately none of this worked, which could be indicative of hardware failure of iPhone and not letting original charger to work.
There are no updates on the issue from Apple on original charges not charging iPhone but some customer have reported that they purchased aftermarket lightning cable for iPhone 7 and it has worked flawlessly. It will sync with iTunes also. You may also try this and Hope this helps.