Perform the following steps if you receive an authentication error message that says something along the lines of "The requested security package does not exist" when attempting to log into a server via Remote Desktop Connection.
- Press Windows key+R to open the Run window.
Type "regedit" and click OK (Registry Editor opens).
- In the tree view, navigate to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa.
Double-click the Security Packages key.
- Verify the following values (in order) are in the Value Data field. Add any values that are missing.
- Click OK.
- Restart the computer.