How can I use my Canon Pixma network scanner?

I have successfully configured a Canon Pixma MX494 as a network printer from my laptop (PureOS/Debian) using CUPS. It appears under "Printers" and I can print a test page over the network. I can successfully scan over the network from my Android device using the Canon app. I am now trying to configure the same device as a *network* scanner from my laptop. Following https://wiki.debian.org/SaneOverNetwork#Client_Configuration I have: * Installed libsane and sane-utils (already installed) * Uncomment the net backend entry in /etc/sane.d/dll.conf (already uncommented) * Added the IP address of the scanner to /etc/sane.d/net.conf (Although, from the link "Note that the net backend is not for accessing arbitrary scanners over a network.") * I can ping the scanner at its IP address from my laptop But scanimage -L does not detect the scanner. (It seemed to detect it once, but simple-scan then failed, and it has not detected it again since then.)