SiteOrigin CSS Plugin not working

I am currently using the Vantage theme on my main site. I installed the CSS Plugin, but when I go to use it neither the visual nor the text editor main window shows up. The “text, decoration, and layout window does show up. “The plugin works fine on my test site. Here are the things I have tried:
1. Disabling all the non-SiteOrigin plugins and clearing cache
2. reinstalling the plugin
One thing that I noticed that was out of place was when I opened the plugin my site shows up as http:. I recently added a domain level SSL certificate that I purchased from Host Gator. I suspect that this might be the issue. Any suggestions would be appreciated.