RDP error: This computer can’t connect to the remote computer

Let’s try to figure out how to fix an RDP connection error This computer can’t connect to the remote computer, which occurs when you are trying to connect to a remote computer or Remote Desktop Server (RDS) using the RDP client.

The problem looks like this: when you are trying to connect via RDP to a remote Windows server, the mstsc.exe client freezes for a minute and a window with the following RDP error appears:

Remote Desktop Connection

This computer can’t connect to the remote computer.

Try connecting again. If the problem continues, contact the owner of the remote computer or your network administrator.

This computer can’t connect to the remote computer

First of all, check that the remote computer is accessible from the client computer over the network and the Remote Desktop port (TCP 3389) is responding (not blocked by firewalls). You can check the RDP port availability on a remote server from client workstation using:

The Telnet client:

telnet rdp_server_name1 3389

PowerShell 4.0 and higher:

Test-NetConnection rdp_server_name1 -Port 3389 -InformationLevel Quiet

PowerShell all versions:

New-Object System.Net.Sockets.TcpClient).Connect(‘rdp_server_name1’, 3389)

If port 3389 is unavailable, you should check that Remote Connections is enabled on the remote server (right click on Start button > System > Remote settings > Allow remote connections to this computer).

If Remote Desktop is enabled, next you should check the setting, which determines the maximum number of simultaneous connections to a Remote Desktop. Open tsadmin.msc mmc snap-in (Administrative tools > Remote Desktop Services > Remote desktop Session Host Configuration). Click on RDP-TCP properties and check the value of Maximum connections property in Network Adapter tab.

Use the netstat command to verify if TCP port 3389 is in Listening state. Open a command prompt as administrator and execute the command:

netstat -a -o|find "LIST"

As you can see, in our example, port 3389 is listening.

TCP 0.0.0.0:3389 DESKTOP-JOPF9:0 LISTENING 1096

In some cases, the administrator can change the default RDP port from 3389 to something else (although this is not recommended by Microsoft). To check the current port on which the Remote Desktop service is listening on the computer, open the registry editor and go to the registry key:

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

Note the value of the PortNumber REG_DWORD parameter. It indicates the current TCP port assigned to the RDP service. In our example, this is 3389 (d3d hexadecimal value). If you have a different port, you can change it to 3389 (in decimal) and restart the computer.

Also, check that the rule allowing incoming RDP connections is enabled in the Windows Firewall settings.

1. To do this, go to the Control Panel\System and Security\Windows Defender Firewall;
2. Press the “Allow an app or feature through Windows Defender Firewall” > Change Settings;
3. Find the Remote Desktop rule and make sure it is enabled for Private and Public networks.

RDP This computer can’t connect to the remote computer: a possible cause

Another possible cause of the RDP error may be a high level of security, which is not supported by older versions of the RDP client.

In this case, open the General tab on the RDP-Tcp properties windows and change the Security layer from default Negotiate to less secure RDP Security Layer.

Tip. Snap-in tsadmin.msc and RDP-Tcp Properties dialog box are missing in Windows Server 2016 and 2012 R2. But you can configure Remote Desktop setting using the local group policy editor (gpedit.msc). The necessary policies are located in the following GPO section: Local Computer Policy > Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host.

• RDP security level can be specified using the policy named Require user of specific security layer for remote (RDP) connections. Enable this policy and in the dropdown select the RDP Security level.

• Maximum number of RDP connection can be specified in the section Connections using policy Limit number of connections. Set unlimited connection by specifying 999999 in the option RD Maximum Connections allowed

In some cases, when connecting with Windows 10 to a remote desktop on Remote Desktop Gateway on Windows 2012 R2, an error occurs:

RemoteApp Disconnected

Your computer can’t connect to the remote computer because an error occurred on the remote computer that you want to connect to. Contact your network administrator for assistance.

To fix this problem, you need to perform the following steps on the RDP client:

1. Open the Registry Editor (regedit.exe);
2. Go to the registry key HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client;
3. Create a DWORD parameter with the name RDGClientTransport and the value 1.
4. Restart the computer.

There is another error related to Remote Desktop Gateway, on which users run RemotApps.

RemoteApp Disconnected.

Your computer can’t connect to the remote computer because the Remote Desktop Gateway server address is unreachable or incorrect. Type a valid Remote Desktop Gateway server address.

To fix this problem:

1. Open the Internet Information Services (IIS) Manager on the Remote Desktop Gateway server;
2. Go to the IIS section Sites > Default Website > RDWeb > Pages > Application Settings;
3. For the DefaultTSGateway value, enter the server’s FQDN public name of your RD Gateway server, and then restart the web services with the command: iisreset

Go back to your client PC and try to start a new RDP Session. The connection should be established successfully.