diff -r 62100f31eb8a -r 0dc80024fdd2 plugins/mod_smacks.lua
--- a/plugins/mod_smacks.lua	Fri Sep 30 20:38:31 2022 +0100
+++ b/plugins/mod_smacks.lua	Mon Oct 03 12:55:11 2022 +0200
@@ -57,6 +57,7 @@
 
 local sessionmanager = require "core.sessionmanager";
 
+local xmlns_errors = "urn:ietf:params:xml:ns:xmpp-stanzas";
 local xmlns_delay = "urn:xmpp:delay";
 local xmlns_mam2 = "urn:xmpp:mam:2";
 local xmlns_sm2 = "urn:xmpp:sm:2";
@@ -647,7 +648,7 @@
 	local resumed, err = do_resume(session, stanza);
 	if not resumed then
 		session.send(st.stanza("failed", { xmlns = xmlns_sm, h = format_h(err.context.h) })
-			:add_error(err));
+			:tag(err.condition, { xmlns = xmlns_errors }));
 		return true;
 	end