diff --git a/mkdocs.yml b/mkdocs.yml
index c31cee31..e547b21d 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -36,8 +36,8 @@ markdown_extensions:
 repo_url: https://github.com/hackingmaterials/matbench
 
 extra_javascript:
-  - https://polyfill.io/v3/polyfill.min.js?features=es6
+  - https://cdnjs.cloudflare.com/polyfill/v3/polyfill.min.js?features=es6
   - https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js
 
 extra_css:
-  - stylesheets/aesthetic_fixes.css
\ No newline at end of file
+  - stylesheets/aesthetic_fixes.css