Apple USB Charger Flickers When Plugged into Computer

I have a 2016 MacBook Pro 15' with Retina, I also have a 2017 Apple iPadPro that I have been trying to connect to my computer with the Apple USB Charging Cable. Every time I plug it in it keeps flickering, and will not charge or connect my iPad to the computer. I have tried the other USB port on the other side, as well as another Apple charger. This also happens to my iPhone. How can I fix this issue? I have also re-booted both devices and tried keeping my Mac plugged in while I tried connecting the USB.