How to Fix RDP NLA (Network Level Authentication) Error Using PowerShell

Introduction

Network Level Authentication (NLA) is a security feature in Remote Desktop Protocol (RDP) that requires authentication before establishing a session. While NLA enhances security, it can sometimes cause login issues, preventing users from connecting to a remote machine.

This blog explains:

What causes the RDP NLA error
How to disable or enable NLA using PowerShell
Troubleshooting common NLA-related issues

What Causes the RDP NLA Error?

The NLA error typically occurs when:
❌ The remote machine cannot authenticate the user due to domain or credential issues.
❌ The remote machine is not part of a domain but still requires NLA.
❌ The remote machine’s security policy enforces NLA, preventing connections from unauthorized clients.
❌ The Remote Desktop Services are misconfigured.

Error Message Example:

“The remote computer requires Network Level Authentication (NLA), but your domain controller cannot be contacted to perform NLA. You must disable NLA on the remote computer in order to connect.”

Fixing RDP NLA Errors Using PowerShell

1️⃣ Temporarily Disable NLA via PowerShell

If you cannot log in remotely, you may need to disable NLA from another computer that has admin access to the remote machine.

Run this command in PowerShell (Admin Mode):

powershellCopyEdit$RemoteComputer = "RemotePCName"

Invoke-Command -ComputerName $RemoteComputer -ScriptBlock {
    Set-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp" -Name "UserAuthentication" -Value 0
    Restart-Service TermService -Force
}

Write-Host "NLA has been disabled on $RemoteComputer. Try connecting again." -ForegroundColor Green

✅ This command disables NLA and restarts the Remote Desktop Services (TermService).

2️⃣ Disable NLA Locally (If You Have Local Access)

If you can physically access the machine, use this PowerShell command:

powershellCopyEditSet-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp" -Name "UserAuthentication" -Value 0
Restart-Service TermService -Force
Write-Host "NLA has been disabled. You can now RDP without NLA requirements." -ForegroundColor Green

3️⃣ Enable NLA Again for Security

Once you resolve the issue, re-enable NLA to restore security:

powershellCopyEditSet-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp" -Name "UserAuthentication" -Value 1
Restart-Service TermService -Force
Write-Host "NLA has been enabled for improved security." -ForegroundColor Green

✅ This ensures only authenticated users can establish an RDP session.

Additional Troubleshooting Steps

✅ Ensure Remote Desktop Services Are Running

Run this command to check RDP services:

powershellCopyEditGet-Service -Name TermService

If it’s stopped, restart it:

powershellCopyEditRestart-Service -Name TermService -Force

✅ Check Firewall Settings for RDP

If RDP is blocked, allow it with:

powershellCopyEditEnable-NetFirewallRule -DisplayGroup "Remote Desktop"
Write-Host "Firewall rules updated. RDP is now allowed." -ForegroundColor Green

✅ Verify Domain Connectivity

If the computer is domain-joined, ensure it can reach the domain controller:

powershellCopyEditTest-ComputerSecureChannel -Server "YourDomainController" -Credential (Get-Credential)

If it’s broken, repair it:

powershellCopyEditReset-ComputerMachinePassword -Credential (Get-Credential)

Best Practices to Avoid RDP NLA Errors

✅ Keep Remote Desktop Services and Windows Updates current.
✅ Ensure that all RDP clients support NLA (older clients may not).
✅ Configure Group Policy to allow fallback connections if needed:

powershellCopyEditgpedit.msc

Navigate to:
Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Security
Set Require user authentication for remote connections using NLA to Disabled (if troubleshooting).

Conclusion

The RDP NLA error is a security feature, but when misconfigured, it can block remote access. PowerShell provides an easy way to disable or enable NLA, restart RDP services, and troubleshoot connectivity issues.

🚀 Did this guide help you? Let me know in the comments!

Jet Mariano