Fix RDP Connection Error 0x204 on Windows, Mac and Linux

RDP connection error 0x204 usually means that the client cannot complete a connection to the remote Windows host. Test the address and TCP port first, then verify that the host is powered on, Remote Desktop is enabled, its listener and firewall rules work, and the account is allowed to sign in.

This guide follows that order on Windows, macOS and Linux so that each result tells you what to check next instead of changing several settings at once.

Before You Change Any Remote Desktop Settings

Record the Exact Address, Port and Error Message

Copy the hostname or IP address supplied for the host, the configured RDP port, the username format and the complete error message. Do not assume the port is 3389 if the server administrator supplied another port; Remote Desktop normally listens on TCP port 3389 unless it has been changed.

Keep a Host-Side Access Method Available

Before changing host settings, keep console, hypervisor, local keyboard or administrator-assisted access available. A firewall, listener or authentication change can otherwise leave you unable to test or reverse the change.

Know When to Stop and Contact the Server Administrator

Stop after you establish that the host is off, its address is unknown, or a network policy blocks the port and you do not administer those systems. Use the related connection guidance on our digirdp knowledge base before making host-side changes you cannot verify.

Step 1: Test the Hostname and IP Address

Connect once using the supplied hostname and once using the supplied IP address, using the same username and port for both attempts. This separates name resolution from the TCP path and the Remote Desktop service.

When an IP Connection Works but the Hostname Fails

If the IP address works while the hostname fails, the likely issue is DNS or name resolution rather than RDP itself. Correct the hostname record or use the current address supplied by the administrator.

Using a Custom Port in the Connection Address

For a non-default listener, enter the target as hostname:port or IP-address:port in the client’s computer or PC field. Test that same port in every later step.

Step 2: Confirm the Remote Windows Host Is Available

Verify That the Host Is Powered On and Awake

Confirm through the host console or administrator that the Windows machine is powered on and not asleep or hibernating. Remote Desktop cannot connect to a computer in those states.

Confirm the Address Has Not Changed

Compare the hostname and IP address in your client with the connection details currently assigned to the host. If the address changed, update the saved client entry and repeat the port test before changing Windows settings.

Step 3: Test RDP Port Reachability from Your Client

Test the exact hostname or IP address and the configured RDP port from the device running the client. A failed TCP test points to the network path, address or firewall; a successful test moves the investigation to the Windows host and sign-in stage.

Windows PowerShell: Test-NetConnection

On the Windows client, open PowerShell and replace the example target and port with the values for your host. Microsoft documents Test-NetConnection for this RDP connectivity check.

Test-NetConnection -ComputerName 203.0.113.10 -Port 3389 -InformationLevel Detailed

Read the TcpTestSucceeded field. A value of True means the TCP test reached the target port; False means that connectivity must be investigated before credentials or client preferences.

macOS and Linux: Test the Target TCP Port

On macOS or Linux, open Terminal and run a TCP probe with the target address and configured port.

nc -zv 203.0.113.10 3389

A successful connection or open-port message means the TCP path is available. A timeout, refusal or unreachable result means the port test did not establish the required connection; check the address, host state, firewall and intervening network policy.

What TCP Success and Failure Tell You

If the TCP test succeeds but error 0x204 continues, continue with the host listener, firewall and account checks. If it fails for both hostname and IP address, do not spend time changing saved credentials until the network path or host-side service is confirmed.

Step 4: Check Remote Desktop, the Listener and Firewall on the Host

Perform these checks from the Windows host console or through an administrator with host access. Enable Remote Desktop only on trusted networks.

Enable Remote Desktop in Windows Settings

On the host, open Settings, then System, then Remote Desktop, and turn on Remote Desktop if it is disabled. Remote connections must be enabled on the target before a client can create an RDP session.

Inspect the RDP Listener and Configured Port

Open an elevated PowerShell window on the host and inspect the configured PortNumber under the RDP-TCP listener key.

Get-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp' -Name PortNumber

Interpret the displayed value as the configured listener port and use that value in the client address and TCP test. Microsoft’s RDP troubleshooting guidance uses the Terminal Server WinStations registry area to inspect this setting and checks that the listener is operating on the expected port.

Enable the Applicable Remote Desktop Firewall Rules

Still in an elevated PowerShell window, enable the Windows Firewall rules in the Remote Desktop display group.

Get-NetFirewallRule -DisplayGroup "Remote Desktop" | Set-NetFirewallRule -Enabled True

Also confirm that the Remote Desktop User Mode TCP-In rule is enabled for the network profile in use. If you need a managed remote Windows environment rather than repair access to this host, review our windows rdp plans.

Step 5: Resolve Credentials, Permissions and NLA Issues

Only move to account checks after the address is correct and the TCP test reaches the expected port. A rejected account can look similar to a connection issue, but it occurs later in the connection process.

Use the Correct Account Format

Use the username format supplied by the host administrator. For a local account, this is commonly HOSTNAME\username or .\username; do not substitute an email address unless that is the account configured on the host.

Check Remote Desktop Users and Logon Rights

Confirm that the account is a member of an allowed group, such as Remote Desktop Users or Administrators, and has the Allow log on through Remote Desktop Services right. An account without the required right or permitted group membership can be rejected.

Review Network Level Authentication Compatibility

Network Level Authentication requires credentials before the RDP session is established. When the port test succeeds but sign-in fails, verify account permissions and that the client can meet the host’s NLA requirement with the server administrator.

Step 6: Use the Right Client Settings on Windows, macOS and Linux

Enter the same verified host, port and account details on every client platform. Remove or edit a saved entry if it contains an old hostname, IP address, port or username.

Windows App and Remote Desktop Connection

In Windows App or Remote Desktop Connection, add or edit the PC entry, enter the hostname or IP address, and append :port when the host uses a non-default port. Microsoft documents Remote Desktop clients for Windows and macOS, with supported features varying by platform.

macOS Connection Details and Saved Entries

In the macOS Remote Desktop client, edit the saved PC entry and confirm the PC name or IP address, port and user account match the tested values. Delete and recreate only the saved entry if it continues to retain an incorrect address or account selection.

Linux xfreerdp Target and Port Syntax

FreeRDP documents xfreerdp as an X11 RDP client and supports target syntax through the /v: option. Run this command from a Linux terminal after replacing the target, port and username.

xfreerdp /v:203.0.113.10:3389 /u:username /clipboard

If the command cannot establish a connection, return to the hostname/IP and TCP-port tests. FreeRDP lists missing network connectivity, no RDP server, firewall blocking and incompatible cipher support among possible connection causes. For another client configuration walkthrough, see Mac, iPhone, and Android RDP.

Troubleshooting Results Matrix

The table below maps each observed result to the next check.

When to Contact the Network or Server Administrator

Contact the network or server administrator when the host is off, you cannot verify the current address, the port test fails outside your administrative boundary, or a listener, firewall or account-policy change requires elevated access. Include the tested target, port, time, client platform and the exact TCP result.

Choose a Windows RDP Plan When You Need a New Host

Match Access Requirements to an RDP Plan

If you need replacement remote Windows access rather than a fix for an existing host, the table below helps you compare the listed DigiRDP RDP options.

Check Available Locations and Plan Details

Inspect current options on Buy RDP, consider Private RDP plans guide if you need a different access arrangement, and check DigiRDP data centre locations guide before selecting a location.

Frequently Asked Questions

What Does Error Code 0x204 Mean in a Windows App?

Error 0x204 indicates that the Remote Desktop client did not complete a connection to the remote host. Start with the hostname or IP address and TCP port test, then check the host listener, firewall and account permissions.

What Does Error Code 0x204 Mean When Using Mac Remote Desktop?

On macOS, error 0x204 should be approached in the same order: verify the saved PC name or IP address, test the target port from Terminal, then confirm Remote Desktop and the firewall on the Windows host. A saved entry with an old address or port can cause the same failure.

Can I Fix RDP Error 0x204 by Using the IP Address Instead of the Hostname?

Using the IP address is a useful diagnostic test. If the IP connection works and the hostname does not, the likely cause is DNS or name resolution; correct the hostname record rather than treating it as a general RDP failure.

How Do I Check Whether Port 3389 Is Reachable for RDP?

On Windows, run Test-NetConnection with the target and port 3389, then read TcpTestSucceeded. On macOS or Linux, use a TCP probe such as nc -zv against the exact target and port. If the host uses another configured port, test that port instead.

How Do I Troubleshoot RDP Error 0x204 on Linux?

First test the target’s TCP port from the Linux device. Then use xfreerdp with /v:host:port and the correct username, and return to the host-side listener and firewall checks if it cannot connect.

Why Is RDP Not Connecting?

Common layers are an incorrect hostname or IP address, an unavailable host, a blocked or incorrect TCP port, disabled Remote Desktop, a listener or firewall problem, or an account and NLA restriction. Testing in that order identifies the earliest failed layer.

Sources

1. Remote Desktop Can't Connect to the Remote Computer - Windows Server | Microsoft Learn — learn.microsoft.com
2. Change Remote Desktop listening port on Windows and Windows Server | Microsoft Learn — learn.microsoft.com
3. Remote Desktop clients FAQ | Microsoft Learn — learn.microsoft.com
4. Enable Remote Desktop on your PC | Microsoft Learn — learn.microsoft.com
5. General Remote Desktop connection troubleshooting - Windows Server | Microsoft Learn — learn.microsoft.com
6. The System Administrator Has Restricted the Types of Logon - Windows Server | Microsoft Learn — learn.microsoft.com
7. Compare Remote Desktop client features across platforms and devices - Remote Desktop client | Microsoft Learn — learn.microsoft.com
8. FreeRDP/client/X11/man/xfreerdp.1.in at master · FreeRDP/FreeRDP · GitHub — github.com