There are many different ways to charge your iPhone — plugging it into your laptop, wall adapter, car charger, and more. As a precautionary measure, the software of your iPhone will prevent charging if it detects fluctuations from the power source.

How Do I Inspect My iPhone Charger?

Charge your iPhone with multiple different power sources. If you normally use your wall charger, try using a USB port on your laptop, and vice versa.
If your iPhone charges with one power source but not the other, then you know that the charger is causing your problem.

Pro Tips

If you're attempting to charge your iPhone using a USB hub or Apple keyboard, plug your iPhone directly into the USB port on your computer. USB hubs and keyboards only have certain amount of power which has to distributed between any of the devices connected to them. If the other devices connected to your USB hub or keyboard are using up too much power, then there may not be enough left to charge your iPhone.