To whoever is on this website looking for answers,
My mother experienced this exact problem where her charcher wouldn't go into the port (she has an iPhone 6s) She tried using different chargers and outlets but it seemed to not be the case. By looking into the port it may look like "there's nothing" but don't be fooled. Grab a flashlight (I used my phones flashlight) and look into the port. If you do not see two little holes at the back of the port (or where you look directly into it) then there's something stuck in there. Get something small like a toothpick and carefully stick the toothpick in the port. Go ahead and scrape around, if you pull the toothpick out and there's gunk on it keep scrapeing around to get the rest out. Now it helps if every once in a while put the charger in to see if it goes in all the way. In my experience there was a waxy thing stuck in it. So I put the toothpick all they way in the "wax" and was able to scrape it out from there. But some cases may be easier or harder. Now if there truthfully is nothing in there go to the Apple Store!