--- a/plugins/muc/muc.lib.lua	Wed Mar 22 12:02:52 2017 +0100
+++ b/plugins/muc/muc.lib.lua	Wed Mar 22 14:13:28 2017 +0100
@@ -496,6 +496,7 @@
 							self.locked = nil; -- Older groupchat protocol doesn't lock
 						end
 					elseif self.locked then -- Deny entry
+						module:log("debug", "Room is locked, denying entry");
 						origin.send(st.error_reply(stanza, "cancel", "item-not-found"));
 						return;
 					end