Version 3.1 is quite old. Can you try to switch to devel ?
binaries are here : https://download.geexbox.org/snapshots/
uncompress the img.xz file and use a tool like win32diskimager if you are on windows.
I suspect the same problem on devel.
Just connect remotely, and edit /etc/opkg/opkg.conf
the line that starts with “src snapshots https://…..” is maybe incorrect
the good one is src snapshots https://download.geexbox.org/snapshots/geexbox-kodi-i386-generic/latest/binaries.i386/packages/