Need to iframe an https layered url on an http site

I'm trying to bring up in an iframe on an http site an https page that has a layered url, in which the last part of the url tells the host site which account is requesting the page.
The url of the target page is:https://www.groupvbs.com/webtoybox/myvbs/hhkcommunitychurch
which then redirects to https://www.groupvbs.com/webtoybox/mysite/default.aspx

If I add https://www.groupvbs.com to "trusted sites" it works, even if I later remove it from trusted sites. But without that, the iframe just hangs and won't load.

Right now I have it set to redirect which is okay but staying on the host site in an iframe would be better. So I'm not sure what I need, but I guess something that tells the browser it's okay to load the page within a iframe.
The host site/page is: http://hohokuscommunitychurch.org/vbs.aspx