Enable proxy, now some pages don't show up

Hi all,
I'm a noob at using proxy servers. I downloaded foxyproxy a couple weeks' ago and just now started using it. When I defined my first proxy, I noticed that some pages will now load REALLY slow. Or some pages won't load at all. Am I doing something incorrectly? I noticed I when COMPLETELY DISABLE foxy proxy, and then re-open firefox, then I'm fine again as far as loading.

Kinda weird,

Thanks

Would it be faster in you

Would it be faster in you disable FoxyProxy and define the proxy used directly in Firefox?