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:Troubleshoot the "Local Security Authority cannot be contacted" error

Last Updated:Apr 16, 2026

This topic describes how to resolve the "An authentication error has occurred. The Local Security Authority cannot be contacted" error when you connect to a Windows instance by using Remote Desktop.

Symptoms

When you use Remote Desktop to connect to a Windows instance from your local computer, you receive the following error message: "An authentication error has occurred. The Local Security Authority cannot be contacted".

Causes

This error can occur for the following reasons:

Resolution

Solution 1: Modify Remote Desktop configuration

  1. Connect to the Windows instance by using VNC.

    For more information, see Connect to an instance by using VNC.

  2. Right-click the Dingtalk_20210510142550.jpg icon and click Run. Enter the sysdm.cpl command to open the System Properties dialog box.

  3. Click the Remote tab. In the Remote Desktop section, select Allow remote connections to this computer, and then click OK.

Solution 2: Modify remote session configuration

  1. Connect to the Windows instance by using VNC.

    For more information, see Connect to an instance by using VNC.

  2. Right-click the Dingtalk_20210510142550.jpg icon, click Run(R), and enter the gpedit.msc command to open the Local Group Policy Editor.

  3. In the Local Group Policy Editor window, navigate to Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Security.

  4. In the Security folder, double-click Require use of specific security layer for remote (RDP) connections.

  5. In the dialog box that appears, select Enabled. From the Security Layer drop-down list, select RDP, and then click OK.

  6. Update the group policy to apply the new settings.

    1. Right-click the Dingtalk_20210510142550.jpg icon, then click Run, and enter the cmd command to open the Command Prompt.

    2. Run the gpupdate command to complete the policy update.

  7. Connect to the instance again to verify that the issue is resolved.

Related documents

Troubleshoot issues when you cannot connect to a Windows instance