Hi I have an outside toilet which it part of my outside sheds. Quite a few years ago the toilet did used to work but now it just doesn’t get any water supply and I don’t know why.
the mechanism of the cistern is blocked it has to be replaced
Is there a stop tap on the pipe work if so see if it's on and if so most likely be the toilet system has stopped working
May be frost damage, or just a stuck ball valve.
Sometimes the float valves can calcify & stick in hard water areas, with being out side & not in frequent use this is quite common. the valve may just need attention or a replacement , a competent plumber will be able to diagnose the issue via a maintenance visit ,
hope this helps , regards Ric
Plan design & build Ltd