Dave from Illinois writes:
My girlfriend and I have gotten new Windows 8.1 tablets for Christmas. We are plugging along learning how to use it. One problem we are having is. Using IE11 when we try to sign on to Yahoo Mail we get back a message stating that there is a setting in IE 11 that will not allow us to display the site requested. This also happens on other sites that require password authentication such as Facebook. I have downloaded FireFox and I am able to view these sites with it. Do you know what setting needs to be changed in IE 11 to allow viewing of these pages?
You aren’t the only person to report this problem. First, make sure all of your Windows 8.1 updates are up-to-date. That fixed the issue for some people.
Others have found it was coming from the enhanced protection mode in Windows 8.1. Here’s how to disable that feature. Open IE and choose Internet Options.
When the Internet Options window opens, select the advanced Tab.
Scroll down to Security and make sure that Enable Enhanced Protected Mode is not checked.
Then hit OK. If that doesn’t help the problem you may want to reset Internet Explorer  or consider uninstalling and reinstalling IE 11.