An authentication error has occurred the function is not supported this could be due to credssp

An authentication error has occurred the function is not supported this could be due to credssp

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One will land to this error while trying to access a computer which do not have credssp encryption oracle Remediation Patch installed. This issue usually arises on windows 10 build 1803.To get this issue resolved one could update the windows to latest available build or to uninstall the security patches and rolled back to an older version when things were in place, both of them are tedious tasks. Lets jump into a an easy fix to this issue.

The issue

Previously one was able to access a non update machine from an updated machine but with a latest Microsoft patch release the subjected issue came in play.

You will face the error “credssp encryption oracle remediation not available” while using RDP Services.


Connecting to server and update it does not make sense as you have to physically access, Instead you have to downgrade the protection level of client machine to vulnerable. You can do this by changing the group policy or editing registry on local computer.

1. Go to “Run” (Win Key + R)
2. Type “gpedit.msc” and click “Enter”

3. Go to Computer Configuration -> Administrative Template -> System -> Credentials Delegation -> Encryption Oracle Remediation

4. Double Click on “Encryption Oracle Remediation”, choose “Enable” and change protection level to “Vulnerable” and click “Apply” or “Ok”

You can also fix the issue with the help of a Windows Registry Editor

1. Open Windows Registry by typing “regedit” in “Run”
2. Navigate to Computer -> HKEY_LOCAL_MACHINE -> SOFTWARE -> Microsoft -> Windows -> CurrentVersion -> Policies -> System -> CredSSP -> Parameters

3. Doubleclick on the Key “Allow Encryption” Change the value to “2”

This method also gives the same output as achieved through the Group Policy Editor. You may use the below table from Microsoft to compare the installed windows update for CredSSP.

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This Post Has 13 Comments

  1. Amjad Hussain

    I found it very helpful. Thanks for sharing.

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