Your printer manual here:
https://files.support.epson.com/pdf/r3000_/r3000_ba.pdf
If you previously set up the product on a wireless network, you must
disable the
wireless connection before you can connect to a wired network. Press
OK then select Setup -> Network Settings -> Wireless LAN Setup -> Disable Wireless LAN
Select Yes, then press OK
You dont say whether USB or Ethernet connection. You dont say Windows or Mac Operating System.
See page 54 for Ethernet connection
Otherwise see page 47
Meant to say also, that you must uninstall any previous attempts to install, before proceeding.
If Windows: Control Panel -> Devices & Printers ->
Right Click R3000 Icon -> Select Remove Device
Proceed with new Install.