--- a/plugins/mod_c2s.lua	Tue May 22 21:22:51 2018 +0200
+++ b/plugins/mod_c2s.lua	Tue May 22 22:25:59 2018 +0200
@@ -172,7 +172,7 @@
 		function session.send() return false; end
 
 		local reason_text = (reason and (reason.name or reason.text or reason.condition)) or reason;
-		session.log("debug", "c2s stream for %s closed: %s", session.full_jid or ("<"..session.ip..">"), reason_text or "session closed");
+		session.log("debug", "c2s stream for %s closed: %s", session.full_jid or session.ip or "<unknown>", reason_text or "session closed");
 
 		-- Authenticated incoming stream may still be sending us stanzas, so wait for </stream:stream> from remote
 		local conn = session.conn;