Turn on TLS 1.0, TLS 1.1, TLS 1.2 ... Asp.NET IIS 10.0

Question

For months, my web application worked just fine on different versions of IE/Firefox/Chrome. My application is running on IIS 10.0. When I hit the application from a Windows 7 box (IE 11.0.***) everything works fine. When I hit the application from Windows 10 box (IE 11.2007.14393.0), it just started giving me this error (was working last week):

This page can’t be displayed Turn on TLS 1.0, TLS 1.1, and TLS 1.2 in Advanced settings and try connecting to https:// again. If this error persists, it is possible that this site uses an unsupported protocol or cipher suite such as RC4 (link for the details), which is not considered secure. Please contact your site administrator.

I have looked this up from many sites and have tried multiple things. Ensured TLS settings, setup Registry on Server to allow TLS, etc. As far as I can tell, there were no updates when this occurred. This is an Asp.NET MVC application targeting DNX Core 1 - rc1. I did not push any updates to the server when it stopped working.

On a Windows 7 box, I show in Firefox that it is using TLS 1.2 for this site (and works fine!)

What could be going on here? I'm out of options to try.

Solution

Morning, a year and a half later.

I just wanted to share my experience (and solution) with this problem. I'm sure there are many reasons for this happening however one thing that i have consistently noticed is the following:

1. Go into iis manager and select the web site that is causing problems ('Default Web Site' in my case)
2. In the Actions pane on the right under 'Edit Site' click on 'Bindings...'
3. Select the https binding and click 'Edit...' on the right
4. Toggle the 'SSL certificate' selection and click ok

If you see an error such as the following:

There was an error while performing this operation. Details: A specified logon session does not exist. It may already have been terminated. (Exception from HRESULT: 0x80070520)

What seems to have happened is the certificate has become corrupt for some reason.
The only thing that I've been able to do to remediate this issue is to remove the certificate from the server using mmc.exe and the certificates add-in (Console Root\Certificates (Local Computer)\Personal\Certificates<the offending certificate>) and re add it in the same location.

The TLS error goes away on the web page.

Comments

[Hanson]

I did this. And it didn't help.