Why Can't I Charge My HTC One M8?

[AC Question]

I can only charge my HTC One M8 if I place a weighted object on the cord, and only then it charges very slowly, and not it only discharges when it says it's charging. Plus, I've tried to charge it with different cords and I am using the HTC Rapid charging block.

 

[belodion]

The connector inside the USB port may be dirty or damaged, among other possibilities.