diff --git a/physics/docs/ccpp_dox b/physics/docs/ccpp_dox
index 6edd31be7..b28746a91 100644
--- a/physics/docs/ccpp_dox
+++ b/physics/docs/ccpp_dox
@@ -232,7 +232,7 @@ FORMULA_FONTSIZE       = 10
 FORMULA_TRANSPARENT    = YES
 USE_MATHJAX            = YES
 MATHJAX_FORMAT         = HTML-CSS
-MATHJAX_RELPATH        = http://cdn.mathjax.org/mathjax/latest
+MATHJAX_RELPATH        =  https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1
 MATHJAX_EXTENSIONS     =
 MATHJAX_CODEFILE       =
 SEARCHENGINE           = YES