I have been using w3 Total Cache with the setting to enable Expires Headers and eTags but they are not being set.
I’m serving images and other media from a sub-domain such as static.example.org served by nginx but it didn’t work even when I was serving these files with Apache from the main domain.
I’ve tried disabling and re-enabling the browser caching settings in the admin without success. What do you suggest?
do you have mod_expires installed and enabled in your apache module?
If you are using Nginx to serve static content then you will need to manually add your expires headers to your Nginx server file.
Example: