Recently Microsoft changed the security in regards to Remote Desktop connections. This was to address a vulnerability that existed with RDP that allowed an attacker to take complete remote control of a Windows PC.
With this came some security changes and you will need to add a registry entry to your machines if you get Security Connection errors in Windows OS and Server OS when you try and use RDP to connect to an older remote machines. When I say older I mean Windows 7 and Server 2008, Windows 8.x might be affected as well.
For more information on CredSSP see this Microsoft article: https://support.microsoft.com/en-ca/help/4056564/security-update-for-vulnerabilities-in-windows-server-2008
In Windows 7 the error looks like the following…
In Windows 10 the error is a little more detailed and looks like this…
To get past this issue all you need to do is add the following registry entry to your machine.
Alternatively here is a reg file in a zip file that you can just run. Make sure you reboot after adding the registry entry.
I created a group policy on my Domain to push this registry entry to all computers.