diff --git a/Source/domainset/cdn.conf b/Source/domainset/cdn.conf
index 98810e0c..bf50ab0d 100644
--- a/Source/domainset/cdn.conf
+++ b/Source/domainset/cdn.conf
@@ -665,6 +665,7 @@ archive.mozilla.org
 detectportal.firefox.com
 stubdownloader.services.mozilla.com
 firefox.settings.services.mozilla.com
+cdn.sso.mozilla.com
 # Mozilla Push
 .push.services.mozilla.com
 # MDN