Pack not working in IE after configuring SSL

We're experiencing issues with the pack after configuring SSL on our sites. Whenever a user tries to log in the page just reloads and then returns to the log in page. However, we are able to access the site if we use a different browser like Firefox.

Any idea on why this is happening?
My guess is that something on the page is being requested over http. The authentication token over https is set to 'https only', so it won't be available to http requests. Requesting the http resource without the cookie will trigger the redirect to the login page. I'm surprised it works in Firefox though.

I'd probably fire up 'Fiddler' to see what's being requested that's causing the redirect. You might also be able to find it with the built in IE developer tools (F12) network tab. You'll have to turn off 'Clear entries on Navigate'.
That's one of the problems: Fiddler is not showing anything. It's as if the user was able to login to the site completely.

I'll have a look again. Perhaps I'm just missing something.


I tested again with Fiddler and here's what I found:

The server responds with this location: /_forms/default.aspx?ReturnUrl=%2f_layouts%2f15%2fAuthenticate.aspx%3fSource%3d%252F&Source=%2F

That's all there is. No errors. Nothing.