CSS not loading

I’m getting an error that my page’s css is not loading because it’s MIME type is text/html and not text/css.

Here’s the error (minus my server name):

The stylesheet http://..myservernamehere…/wp-admin/admin-ajax.php?action=siteorigin_panels_post_css&post=11&layout=4953801e was not loaded because its MIME type, “text/html”, is not “text/css”.

I didn’t add any new plugins prior to this error. The only thing I’ve done was make changes to my stylesheet which should have no effect on the plugin itself.

URL: http://faithinmarketing.pairserver.com/stmarks/