There are two problems:
I found in the prosody of my VPS version not have the hook “muc-occupant-pre-join”, so it can’t handle the module:hook(“muc-occupant-pre-join”, check_for_max_users, 10), I guess I should upgrade prosody in my VPS, but the version of prosody is 0.9.10. It seems to use this hook in 0.10 or newer version. I installed prosody with jitsi(use the method in quick-install.md), need I upgrade prosody?
How can I send the message to the client, what does this one mean? “event.origin.send(st.error_reply(stanza, “cancel”, “service-unavailable”))”, How can I add some event operation functions in the web-client to tell the client the prosody not allow to join.