Error:

An authentication error has occurred.
The function requested is not supported

Remote computer: <computer name=””>
This could be due to CredSSP encryption oracle remediation.
For more information, see https:/go.microsoft.com/fwlink/?linkid=866660

Since the Microsoft Security Patch on Tuesday, we’ve received many reports of users having connection problems like this: 

The error impacts:

• Remote Desktop Connection
• Remote Desktop Connecting to Azure VMs
• VPN Network Connections (before one can even try to use Remote Desktop)

Fix: 

1. On your Local Computer
2. Open up RUN
   
3. Type in:

   gpedit.msc

   

4. Navigate to the following Computer Configuration.Computer Configuration / Administrative Templates / System / Credentials Delegation
5. Double click on Encryption Oracle Remediation– 1 Enable Encryption Oracle Remediation
   – 2 Change Protection level to: Vulnerable

   

Any issues – please post in the comments below.