: One of the most documented "hidden" causes is an expired self-signed certificate on the host machine. If the certificate used to encrypt the RDP session has lapsed, the client will reject the connection with a 0x904 error.
To fix the issue permanently, it helps to understand what is breaking behind the scenes. Windows telemetry logs usually trace this error back to four core areas:
This error message is a classic "generic" failure that typically points to a disconnect between your client and the remote host, often surfacing after Windows 11 updates or in complex network environments : One of the most documented "hidden" causes
Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Security
This error is particularly common in Windows Virtual Desktop (Azure Virtual Desktop) environments where the gateway fails to hand off the session. Phase 1: Quick Fixes (The "Easy Wins") Before diving into registry edits, try these basic steps: Windows telemetry logs usually trace this error back
Resolving this error requires a systematic approach, as the cure depends on the cause. The first line of defense is clearing the local RDP license cache. On the client machine, deleting the MSLicensing registry key (under HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client ) forces the creation of a fresh license on the next connection. For many users, this single step resolves both codes immediately.
Under the operations panel, select and select RunPowerShellScript . On the client machine, deleting the MSLicensing registry
The "Socket closed" error usually originates from a few key areas:
(Alternatively, use PowerShell: restart-service termserv -force )
This solution is designed to handle mismatched security protocols and is a direct fix when the error appears after an OS upgrade.