diff --git a/src/api/app/controllers/webui/groups/users_controller.rb b/src/api/app/controllers/webui/groups/users_controller.rb
index 4a321114f2b..37ecb69415c 100644
--- a/src/api/app/controllers/webui/groups/users_controller.rb
+++ b/src/api/app/controllers/webui/groups/users_controller.rb
@@ -37,7 +37,7 @@ def update
             flash.now[:success] = "Gave maintainer rights to '#{@user}'"
             render 'flash', status: :ok
           else
-            flash.now[:error] = "Couldn't make user '#{user}' maintainer: #{group_maintainer.errors.full_messages.to_sentence}"
+            flash.now[:error] = "Couldn't make user '#{@user}' maintainer: #{group_maintainer.errors.full_messages.to_sentence}"
             render 'flash', status: :bad_request
           end
         else