Hyper-V Manager – Connect to VM CredSSP error

[Window Title]
Remote Desktop Connection

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

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

The most annoying part about this was everything was fine

So I did the usual checks

1. Make sure the Windows Remote Management (WS-Management) Service is running

2. verify that CredSSP is enabled

3. Review the current settings

4. Make sure delegation is allowed from the host hyper-v server

Everything looked ok

Finally I stumbled on this MS article on credssp remediation error when RDP

Made the necessary registry key and value here
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters
“AllowEncryptionOracle”=dword:00000002

There is no reboot required, it worked immediately.
Yes you may now be vulnerable to the encryption oracle attack see Microsoft here

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