I already installed the mod, and it's working properly. But today, when my friend hosted the game, the mod UI didn't show up in my game or my friend's game.

These are too few details to be able to say anything.
logfile, error message, anything?
Enabled in settings? try to disable/enable (with restart in between)
try to use /kpr-add-instance
If you start the same network savegame alone, does it work?

These are too few details to be able to say anything.
logfile, error message, anything?
Enabled in settings? try to disable/enable (with restart in between)
try to use /kpr-add-instance
If you start the same network savegame alone, does it work?

Thank you for your response. There is no error or anything, it just don't show up. I tried Disable/Enable on Mod setting with Restart game few times, still don't show up. Try host save file and play offline, don't show up.

try to use /kpr-add-instance

When I use this console command, the UI show up. I think you should include this command on the FAQ for weird case like mine. Thank for your help.