diff --git a/Troubleshooting.md b/Troubleshooting.md
index b965f4b..7e5be83 100644
--- a/Troubleshooting.md
+++ b/Troubleshooting.md
@@ -27,7 +27,7 @@ Check the following:
 2. **If you are serving Font Awesome from your own server**: both `font-awesome.css` file and `/fonts` folders are up to date;
 3. **If you are serving Font Awesome from a CDN**: Font Awesome's css link is up to date (ref: [#1490](https://github.com/FortAwesome/Font-Awesome/issues/1490));
 4. You are not using plugins/extensions which are loading older/modified versions of Font Awesome (ref: [#1546]( https://github.com/FortAwesome/Font-Awesome/issues/1546));
-5. You are using valid [HTML5](http://www.w3.org/TR/html5/introduction.html#a-quick-introduction-to-html) templates;
+5. You are using valid [HTML5](http://www.w3.org/TR/html5/introduction.html#a-quick-introduction-to-html) templates (check the [W3C Markup Validator](https://validator.w3.org/));
 6. Your browser's development console shows that you are loading the proper font files;
 7. Your browser's extensions are not blocking webfonts (noscript, adblockplus, etc.);
 8. Your operating system is not blocking webfonts (Microsoft Group Policy).