Do You know how to fix CredSSP Authentication Error in RDP ?

Microsoft has already released some security patches in year of March 2018 to repair the precise vulnerabilities for the CredSSP (Credential Security Support Provider Protocol) employed by the Remote Desktop Protocol in Windows Server. But a recent update has made CredSSP Authentication error in RDP and caused hindrance to several users.

Microsoft pushed the update of May 2018 to harden the protection by making it mandatory for both client and server computers to possess the update installed. This resulted in windows servers not accessible via RDP for several users and made many to reboot their servers to repair the matter thinking it as a server side issue. This blog will facilitate your on the way to repair the CredSSP Authentication related error in Remote Desktop Protocol (RDP)

What is CredSSP?

“CredSSP” or “Credential Security Support Provider Protocol” could be a security support provider which helps to securely delegate user credentials from a client computer to a windows server by using TLS (Transport Layer Security) as an encrypted pipe.

Why the update?

The update in May is formed to correct how CredSSP validates requests during the authentication process. Microsoft has found a credssp error in rdp and located a fix for the vulnerability by mandatory requiring to update both the client and server computer to figure properly.


An authentication error has occurred.

The function requested isn't supported

Remote computer:

This could ensue to CredSSP encryption oracle remediation.

For more information, Click on the link

This error is thanks to the windows update not installed either on the server or on the client computer.


How to fix it?

To fix the issue, you need to uninstall the update and roll back to an older version. But rolling back to an old version is not a best practice. You can fix this by changing the group policy in the local computer to use the vulnerable setting

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.