This error occurs if you are trying to establish an insecure RDP connection, and the insecure RDP connection is blocked by an Encryption Oracle Remediation policy setting on the server or client. This setting defines how to build an RDP session by using CredSSP, and whether an insecure RDP is allowed.
Note: Every step is done on the local computer.
The most common scenario is that the client has the CredSSP update installed, and the Encryption Oracle Remediation policy setting does not allow an insecure RDP connection to a server that doesn’t have the CredSSP update installed.
Select Start Button, type run and enter.
Type gpedit.msc, and then navigate to Computer Configuration – Administrative Templates – System – Credentials Delegation in the left panel.
Double click on Encryption Oracle Remediation policy and change it to Enabled, and then change Protection Level to Vulnerable and apply.
Type CMD in the Window search bar and then gpupdate and enter.
NOTE: Windows 10 Home version doesn’t have Local Group Policy Editor, therefore you can make the same change by using the registry.
a. Type CMD in search and open with right click as administrator
b. Copy/paste the following command to add a registry value and type enter
REG ADD HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters\ /v AllowEncryptionOracle /t REG_DWORD /d 2
You are done! Reboot your PC and the registry value is now added.