Sitemap is Empty

I added an SSL Certificate yesterday to the above website. While trying to update analytics and webmaster tools, I discovered that the sitemap is empty. This message is showing on my xml sitemap page:
There is still a sitemap.xml or sitemap.xml.gz file in your site directory. Please delete them as no static files are used anymore or try to delete them automatically.
I have tried to delete. It looks like it works then comes back again.

I don’t know if this is related to my SSL update or if this is a problem I found only because of the SSL update. I have pretty good ranking for this site and don’t want it to be compromised by a missing sitemap.

The page I need help with: [log in to see the link]