Glad to hear it.
I haven't heard of an external hard drive using an ethernet cable before, as normally they attach to the router by USB only. Is it possible it's a power cable instead?
There is more information here that may apply so you know your full range of options: How to Connect External Hard Disk to Home Network over WiFi without PC | Technical Tips.
Perhaps easiest is to set up a homegroup and then from your PC right click the External to share it with Homegroup: How to set up and manage Windows 10 HomeGroup on a local network | Windows Central
I hope this helps.