How do I troubleshoot a redirect loop issue on MU

I am using the domain mapping plugin and Woocommerce. On ssl pages I get a redirect loop. I did find a note about that on the Woo site http://docs.woothemes.com/document/ssl-and-https/, however the problem only began after upgrading the domain mapping plugin to the latest version. How can I troubleshoot the issue. I'm not sure if it is Woocomerce, the plugin or my host.