When managing Windows servers or connecting to a remote workstation, you might encounter a frustrating error message: "The remote computer requires Network Level Authentication (NLA)." Even when your settings seem correct, finding that RDP NLA not working with NLA enabled can halt your productivity and block critical access.

This guide explores the root causes of NLA failures and provides step-by-step solutions to restore your Remote Desktop Connection.

What is Network Level Authentication (NLA)?

Network Level Authentication (NLA) is a security method that finishes user authentication before you establish a full Remote Desktop session and the login screen appears.

• Security: It protects the remote computer from Denial of Service (DoS) attacks and minimizes the risk of unauthorized access.
• Efficiency: It uses fewer resources by authenticating the user before a full session is created.
• The Conflict: While highly secure, it requires both the client and the server to have matching security protocols (specifically CredSSP).

Common Reasons for "RDP NLA Not Working"

Several factors can trigger this connection failure, ranging from security updates to network misconfigurations:

• CredSSP Protocol Mismatch: Often caused by the "Encryption Oracle Remediation" security update (CVE-2018-0886).
• Domain Controller Connectivity: The client or server cannot reach the Active Directory to verify credentials.
• Corrupted RDP Certificates: The self-signed certificate used by the Remote Desktop service has expired or is buggy.
• Incorrect Group Policy Settings: NLA might be enforced on the server, but not supported or enabled on the client.
• DNS Issues: Failure to resolve the hostname correctly prevents the authentication handshake.

How to Fix RDP NLA Not Working [7 Fixes]

If you are encountering Network Level Authentication (NLA) errors, follow these fixes in order. These methodical approaches help restore access while preserving system security.

Fix 1: Confirm NLA Support on Client and Server

First, ensure that both endpoints are technically capable of handling NLA.

Step 1. Check OS Version: Run winver on both machines to confirm they are running Windows Vista / Windows Server 2008 or later.

Step 2. Update Clients: Ensure the latest Remote Desktop client updates are installed via Windows Update or the official Microsoft Remote Desktop app.

Step 3. Third-Party Apps: If using non-Windows RDP clients, verify that NLA support is explicitly enabled in the settings.

Step 4. Upgrade Plan: If a component does not support NLA, plan for an upgrade rather than permanently lowering security.

Fix 2: Verify Connectivity to Domain Controller

For domain-joined machines, a broken connection to the Active Directory (AD) often triggers NLA failures.

Step 1. Test Reachability: Use ping dc01.yourdomain.com to check the network path to your Domain Controller.

Step 2. Locate DC: Run nltest /dsgetdc:yourdomain.com to confirm the client can discover a DC.

Step 3. Check Secure Channel: Run PowerShell as Administrator and enter:

• Test-ComputerSecureChannel

Step 4. Repair Trust: If the result is False, repair the secure channel using:

• Test-ComputerSecureChannel -Repair -Credential (Get-Credential)

Step 5. Reboot: Reboot the machine after the repair if prompted.

Fix 3: Align CredSSP Patch Levels and Policies

Mismatching CredSSP updates between the client and server is the most common cause of the "Encryption Oracle Remediation" error.

Step 1. Install Updates: Ensure all cumulative security updates are installed on both endpoints.

Step 2. Configure GPO: Open gpedit.msc and navigate to:

• Computer Configuration > Administrative Templates > System > Credentials Delegation.

Step 3. Adjust Remediation: Double-click Encryption Oracle Remediation. Set it to Enabled and, for temporary testing, set the Protection Level to Vulnerable.

Step 4. Long-term Fix: Once connectivity is restored, prioritize patching all systems to a consistent level and revert the policy to Mitigated.

Fix 4: Enable and Validate Required TLS Protocols

NLA relies on modern security protocols. If TLS 1.2 is disabled, the handshake will fail.

Step 1. Registry Verification: Navigate to the following path in the Registry Editor:

• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client

Step 2. Enable Key: Ensure the Enabled DWORD is set to 1.

Step 3. Server Keys: Verify similar settings in the Server subkey under the same path.

Step 4. Certificate Check: Ensure the RDP certificate is valid and not using deprecated signatures. Restart the Remote Desktop Services in services.msc to refresh the certificate.

Fix 5: Review and Adjust Group Policy Settings

Group Policy Objects (GPOs) may enforce NLA in a way that conflicts with your specific environment.

Step 1. Local Security Policy: Open gpedit.msc and navigate to:

• Computer Configuration > Windows Settings > Security Settings > Local Policies > Security Options.

Step 2. Audit Enforcement: Check the policy "Require user authentication for remote connections by using Network Level Authentication".

Step 3. Check Cryptography: Ensure policies regarding FIPS-compliant algorithms are not blocking the connection.

Step 4. Sync Policy: Match NLA enforcement levels with the capabilities of your authorized client devices.

Fix 6: Reset RDP Client and Network Configuration

If the issue is isolated to a specific device, perform a local reset.

Step 1. Clear Cached Settings: Delete the hidden Default.rdp file located in %userprofile%\Documents.

Step 2. Reset Credentials: Open Windows Credential Manager and remove any saved RDP entries.

Step 3. Verify Firewall: Confirm TCP Port 3389 is open on local firewalls and intermediate network hardware.

Step 4. Cross-Test: Attempt a connection from a different client on the same network to determine if the issue is device-specific.

Fix 7: Temporarily Disable NLA to Recover Access

If you are completely locked out of a critical server, you can temporarily disable NLA to perform repairs.

Step 1. Methods: Boot into Safe Mode with Networking or use recovery media to load the system hive.

Step 2. Registry Modification: Navigate to:

• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp

Step 3. Change Value: Set UserAuthentication to 0.

Step 4. Security Warning: This exposes your server to brute-force attacks. Fix the root cause immediately and re-enable NLA (set the value back to 1) as soon as possible.

Bonus Tip: Use AnyViewer as a Reliable RDP Alternative

If you are tired of troubleshooting NLA errors or need an urgent connection to a remote server without diving into Registry or Group Policy edits, AnyViewer is a powerful, professional-grade alternative to Windows Remote Desktop.

Unlike RDP, which relies heavily on complex Windows-specific protocols like CredSSP and NLA, AnyViewer uses its own optimized connection technology to bypass these common handshake failures while maintaining high-level security.

• Why it works: AnyViewer does not require NLA to be configured on the host. It uses Elliptic Curve Cryptography (ECC) encryption to protect your data from end to end, ensuring security without the RDP configuration headaches.
• Ease of Use: It works across different networks (including over the internet) without the need for port forwarding or VPNs.
• Performance: It offers high-speed file transfers and low-latency remote control, making it ideal for both IT support and remote work.

How to set up AnyViewer:

Step 1. Download and Install: Install AnyViewer on both the local and remote Windows machines.

Step 2. Create an Account: Sign up for a free account and log in on both devices.

Step 3. Connect: In the "Device" tab, find the remote computer and click "One-click control" to establish an unattended remote access session.

By using AnyViewer, you can bypass "RDP NLA Not Working" errors entirely and get back to work in minutes.

Conclusion

Navigating NLA errors can be a complex task involving deep system configurations. While fixing the root cause, such as CredSSP mismatches or DNS issues, is the best path for long-term server health, having a reliable backup like AnyViewer ensures that a single protocol error doesn't lock you out of your critical infrastructure.

Always remember to re-enable security features once your troubleshooting is complete to keep your network environment robust and protected.

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