Wi-fi and ethernet aren't playing nice with each other

[ringster]

Since acquiring a wi-fi router (Archer C7A7) I am unable to use my ethernet, it just doesn't work. The lights lite up, even system prefs - network shows ethernet up and running, but I cannot connect to anything until I unplug my ethernet cable. I'm using a Mac mini (late 2012) and running Catalina 10.15.7. Help me please....

 

[Cory Cooper]

Hello,

-I assume you mean a TP-Link Archer C7 or A7?
-Where are your Ethernet cables plugged into the router? WAN should come from modem and LAN should go to devices like your Mac mini.
-Are you using DHCP in the Network preference pane, and not static IPs?

C