sumnersaf For wifi I don't know.
I have an Epson Xp-257 connected with a USB cable.
Look first if in the simple-scan preferences you don't have several choices.
To make my scanner work I modified several files.
/etc/sane.d/dll.conf
/etc/sane.d/epson,conf
/etc/sane.d/epson2.conf
/etc/sane.d/epsonds.conf
In a terminal do lsusb to know the ID of your scanner.
For me it gives you
Bus 002 Device 003: ID 04b8:113d Seiko Epson Corp. XP-255 257 Series
Then modify the files epson.conf, epson2.conf, epsonds.conf.
Which gives me something.
and finally restart your computer.
My /etcMy /etc/sane.d/dll.conf file
/sane.d/dll.conf file