Troubleshooting Remote Desktop (RDP) Connection Failures on Windows Server

Problem Description

Users may encounter an inability to connect to a Windows Server via Remote Desktop Protocol (RDP). Common error messages include "Remote Desktop can't connect to the remote computer," "The remote computer is not available," or authentication failures. This can disrupt remote administration and critical workflows.

English: Remote Desktop Connection fails. The server may be offline, the RDP service is stopped, a firewall blocks the port, or network policies are misconfigured.

Русский: Подключение через удалённый рабочий стол не удаётся. Сервер может быть офлайн, служба RDP остановлена, брандмауэр блокирует порт или сетевые политики настроены неправильно.

中文： 远程桌面连接失败。服务器可能处于离线状态，RDP服务已停止，防火墙阻止了端口，或者网络策略配置错误。

Solution Steps

1. Verify Basic Network Connectivity

1. Ensure the target server is powered on and connected to the network.
2. From your local machine, open Command Prompt and run: ping [Server_IP_or_Hostname]. If the ping fails, check the server's network configuration, cables, and switches.
3. Confirm you are using the correct server IP address or hostname.

2. Check the RDP Service Status on the Server

1. If you have console access (e.g., via IPMI/KVM or cloud provider console), log in to the server.
2. Press Win + R, type services.msc, and press Enter.
3. Locate the Remote Desktop Services (TermService) service. Its status should be "Running". If not, right-click it and select Start.
4. Also ensure the Remote Desktop Services UserMode Port Redirector service is running.

3. Configure Windows Firewall

1. On the server, open Windows Defender Firewall with Advanced Security.
2. Click Inbound Rules. Ensure the rule for Remote Desktop - User Mode (TCP-In) is enabled for the correct network profile (Domain/Private/Public).
3. If the rule is missing, create a new rule: Port > TCP > Specific port: 3389 > Allow the connection.

4. Verify RDP is Enabled in System Settings

1. On the server, go to Settings > System > Remote Desktop.
2. Ensure Enable Remote Desktop is toggled On.
3. Under "User accounts," confirm that the specific user or group you are trying to connect with is listed. If not, add them.

5. Check for Conflicting Group Policies or Port Changes

1. Run gpedit.msc to open the Local Group Policy Editor.
2. Navigate to: Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Connections.
3. Ensure "Allow users to connect remotely by using Remote Desktop Services" is set to Enabled.
4. If a non-default RDP port is used, ensure the firewall rule and client connection specify that port (e.g., Server_IP:Port).

Additional Tips

• Network Level Authentication (NLA): If you receive an authentication error, try disabling NLA temporarily on the server (in the Remote Desktop settings) to test. Ensure the client supports NLA if it is required.
• Check for IP Address Restrictions: Some servers are configured to allow RDP only from specific IP addresses. Verify this in the firewall rules or any third-party security software.
• Restart the RDP Service: A simple restart of the "Remote Desktop Services" service can resolve transient issues.
• Event Viewer Logs: For persistent issues, check the Windows Event Viewer (eventvwr.msc) under Applications and Services Logs > Microsoft > Windows > TerminalServices-LocalSessionManager for detailed error codes.
• Security Software: Temporarily disable any third-party antivirus or firewall software to rule out interference.