are allowed through the Windows Firewall for both Private and Public profiles. Switch Profile: If your network is set to "Public," change it to in Windows Settings to allow RDP traffic more easily. Test the Port:
: Modern Windows updates introduce encryption cipher and Network Level Authentication (NLA) updates that conflict with older host configurations.
If you are trying to connect to a remote computer using Remote Desktop Protocol (RDP) and are stopped by error code 0x904, it indicates a session conflict. Essentially, the remote computer thinks you are already logged in locally (physically at the machine) or in another session, and it cannot create a new connection for you.
Expired self-signed certificates are the most common driver behind this error. Purging the stale certificate forces Windows to dynamically install a new one. i remote desktop connection error code 0x904 install
| Component | Role | Failure point with 0x904 | |-----------|------|---------------------------| | tscupgrd.exe | Upgrades RDP client version | Writing new mstscax.dll to System32 | | licmgr.exe | Manages RDP licenses | Creating MSLicensing registry hive | | RDPActiveX.msi | Installs RDP web control | Extracting to %ProgramFiles%\Remote Desktop | | dism.exe / cbs.dll | Servicing stack | Finalizing RDP feature installation (FOD) |
If it shows “Not Installed” — there’s your problem.
Rename-Item -path "C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys" -NewName "MachineKeys_old" Reboot the server. Windows will recreate the folder and repair the store. 3. Bypass DNS with IP Address (Windows 11 Fix) are allowed through the Windows Firewall for both
: If the server is dropping requests, you can increase the MaxOutstandingConnections in the registry at HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server . Troubleshooting the "Dodgy" Connection
In the Azure Portal, use the Run Command feature to execute this PowerShell script: Rename-Item -path "C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys" -NewName "MachineKeys_old" .
:: Check for read-only System32 attrib %WinDir%\System32\mstsc.exe If you are trying to connect to a
Insufficient bandwidth, high packet loss, or slow VPN connections. TLS/Cipher Mismatches:
On the host computer, press Win + R , type certlm.msc , and navigate to Remote Desktop > Certificates .