diff --git a/dev/templates/legacy.pug b/dev/templates/legacy.pug
index 14f9d489..69ebe948 100644
--- a/dev/templates/legacy.pug
+++ b/dev/templates/legacy.pug
@@ -52,7 +52,7 @@ html
 
     script(
       crossorigin='anonymous'
-      src='https://polyfill.io/v3/polyfill.min.js?features=EventSource'
+      src='https://cdnjs.cloudflare.com/polyfill/v3/polyfill.min.js?features=EventSource'
     )
 
     //- JS