Better !!link!!: I Remote Desktop Connection Error Code 0x904

Firewalls frequently block RDP ports (default is port 3389) during routine security updates.

Or simply: Error code: 0x904 .

Microsoft frequently rolls out stability patches for Remote Desktop Services. Ensure both the local machine and remote host are running the latest Windows updates.

Go to: Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Security .

Incorrect port assignments in the Windows Registry can prevent successful handshakes. Press Win + R . Type regedit . Press .

Are both computers on the , or are you connecting over the internet ?

If you control the remote Windows Server:

Short version for social post: "Getting Remote Desktop error 0x904? Try restarting both PCs, confirm network access and correct credentials, ensure RDP & NLA settings match on client/server, open TCP 3389 in firewalls, update Windows/RDP client, and check Event Viewer for details. If needed, test from another device or adjust NLA temporarily to isolate the problem."

If the above steps don't resolve the issue, try these additional solutions:

The client machine may have a corrupted license cache.

Locate the , NAT , or Virtual Server settings tab. Create a new rule: External Port: 3389 Internal Port: 3389 Protocol: TCP (or TCP/UDP dual mode)