Microsoft Security patch (CredSSP updates for CVE-2018-0886) issued on Tuesday, May 8th 2018 triggered the following RDP problem.
“An authentication error has occurred.
The function requested is not supported
Remote computer: <computer name>
This could be due to CredSSP encryption oracle remediation.
For more information, see https:/go.microsoft.com/fwlink/?linkid=866660”
It changed the default setting from Vulnerable to Mitigated. If your PC received this update but the target PC hasnot implemented the CredSSP update, you will get this error message when trying to connect to the target PC.
- You can roll back the security update, risking other security issues.
- There is a quick fix/workaround for this issue.
- Start cmd as an administrator
- Run the following from the command prompt
“/f/v AllowEncryptionOracle /t REG_DWORD /d 2