If you have the router in Hub mode you to check
Digi TransPort WR44-L400-TE1-RD Ser#:
Software Build Ver184.108.40.206. Mar 7 2019 06:59:24 LW
ARM Bios Ver 7.66u v45 800MHz B995-M1003-F80-O1,0 MAC:00042d04fa31
Async Driver Revision: 1.19 Int clk
Wi-Fi Revision: 2.0
Ethernet Hub Driver Revision: 1.11
Firewall Revision: 1.0
as you see above you will see "Ethernet Hub Driver"
in this mode the ports on the back of the router LAN 0-3 are linked to all eth interfaces so when plugging cables into the router all ports are connected to all interfaces so it does not matter which port cables are plugged into in most cases.
if it is in port isolate mode then
eth 0 -> Lan 0
eth 1 -> Lan 1
eth 2 -> lan 2
eth 3 -> Lan 3
eth 4 and above -> eth 0
in this case you have to be sure you have the correct network cable in the correct port.
so pluging a cable in to the router and want it to get an ipaddress on eth interface you would have to look at hub goups to make sure eth 1 is in a diffrent hub group and in advanced is set to the correct physical port
then it should pickup an ip address.