Ethernet Port Issues

I just purchased the M6 Pro Nighthawk Mobile router MR6550

I have a work phone plugged into the Ethernet port for my remote work. When I plug my phone into the router (no battery inserted- router plugged into power) the service keeps getting disconnected every 5 min or so. It does not happen unless the phone is plugged into the Ethernet port.

This might be an easy fix - I am just not very tech savvy.