external hard drive loses connection while downloading is there a problem with hard drive or usb cable?

i use external usb hard drive and download most of my data in that drive. but while downloading it loses connection sometime and then i have to re-attach it with my pc and it starts working, is there a problem with hard drive itself or the usb cable is droping connection? help me how to fix it?

Sol :-

Most of USB ports works correctly and there might be problem of USB cable which was not inserting properly in to USb ports and try it with different USB port.

There might be a problem of hard disk aswell, check it with a different port and different USB cable.

Scan the hard disk for error checking and defragment it twice in a month.