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During Remote Desktop, the error “An authentication error has occurred. The function requested is not supported” appears, as shown in the figure:

This is caused by one side—either the local client or the server—having updated the CredSSP patch for CVE-2018-0886 while the other side has not installed the update. For details, see:

https://support.microsoft.com/zh-cn/help/4093492/credssp-updates-for-cve-2018-0886-march-13-2018 

The solutions are as follows (Method 1 is strongly recommended).

Method 1 (Strongly Recommended):

Install the update patch on both the local computer and the server at the same time. After updating, restart the server.

Standalone patch download addresses:

win 7, win2008 R2: KB4103718 

win 8, win2012: KB4103730

win10, win2016: KB4103721

Note: Download and install the patch for the corresponding version.

Method 2:

Note: If the local computer does not have this item, it is strongly recommended to install the patch locally according to Method 1; if the local computer has this option, it is strongly recommended to install the patch on the server according to Method 1.

In some special cases, the server cannot update to the latest patch. You can set up the local computer as follows and then log in remotely:

Type gpedit.msc in Run to open policies

Find this path: "Computer Configuration" -> "Administrative Templates" -> "System" -> "Credentials Delegation". In the settings list on the right, find "Encryption Oracle Remediation" and change the Protection Level to "Vulnerable".

After modification, type gpupdate in Run to update the policy.

Some users may have an English interface; for the English interface, configure as shown in the figure.

III. If the local system is win7, and does not have the [Encryption Oracle Remediation] option, please first create a file such as reg.txt, add the following code to the file and save it. After saving, change the .txt extension to .reg, then double-click reg.reg to import it into the registry and restart the computer.

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters]
"AllowEncryptionOracle"=dword:00000002

```