diff -r aa119de5f6c7 -r d117b92fd8e4 plugins/muc/muc.lib.lua
--- a/plugins/muc/muc.lib.lua	Sat Jul 03 03:27:57 2021 +0200
+++ b/plugins/muc/muc.lib.lua	Thu Jul 22 17:18:39 2021 +0200
@@ -976,7 +976,7 @@
 		-- e.g. an admin can't ask for a list of owners
 		local affiliation_rank = valid_affiliations[affiliation or "none"];
 		if (affiliation_rank >= valid_affiliations.admin and affiliation_rank >= _aff_rank)
-		or (self:get_whois() == "anyone") then
+		or (self:get_members_only() and self:get_whois() == "anyone" and affiliation_rank >= valid_affiliations.member) then
 			local reply = st.reply(stanza):query("http://jabber.org/protocol/muc#admin");
 			for jid in self:each_affiliation(_aff or "none") do
 				local nick = self:get_registered_nick(jid);