The most common cause for error 0x904 is an expired self-signed certificate that the Remote Desktop Service uses for encryption.
Many users find that the Microsoft Remote Desktop app from the Microsoft Store is unaffected by the bugs hitting the legacy mstsc.exe client. 5. Adjust Security Layers (GPO)
Explicitly add C:\Windows\System32\mstsc.exe to your firewall's allowed list. i remote desktop connection error code 0x904 better
Log into the affected host locally or through an alternative remote tool.
Identify the expired certificate, right-click it, and select . The most common cause for error 0x904 is
Select and enter: Rename-Item -path "C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys" -NewName "MachineKeys_old" .
Try connecting using the remote machine's internal or external IP address (e.g., 192.168.1.50 ) instead of its computer name. and select .
Even if RDP is technically enabled, specific firewall rules or third-party security software (like Bitdefender) might block the mstsc.exe process.