Overzealous local firewalls, corporate firewalls, or antivirus software may flag the RDP traffic as suspicious and terminate the connection.
: Use the latest Remote Desktop app from the Microsoft Store.
Ensure "Automatically detect RD Gateway server settings" is selected, or turn it off if you are connecting purely over a local network.
RDP uses both TCP and UDP packets. If a router or VPN drops the UDP packets during the handshaking phase, error 0x904 occurs. Switching to TCP fixes this stability issue. Press Windows Key + R , type gpedit.msc , and press Enter . RDP uses both TCP and UDP packets
the virtual machine from the portal interface to automatically trigger key regeneration.
"Require user authentication... using Network Level Authentication (NLA)" Microsoft Learn 🌐 Network & Environment Checks Use IP instead of Hostname:
Prevention and resilience (short)
Are you connecting over a or via a VPN/Internet connection?
Whether you are connecting from a local workstation or trying to access a critical environment like Microsoft Azure VMs or a corporate Windows Server, this guide covers the underlying causes and provides a step-by-step diagnostic roadmap to resolve it. Primary Causes of Error 0x904 (0x7)
The Remote Desktop Protocol (RDP) error is a critical connection failure that typically indicates an expired or corrupted RDP security certificate, network instability, or security handshake blocking between the client machine and the target host . Press Windows Key + R , type gpedit
The target machine may have reached its maximum concurrent RDP sessions (e.g., Windows 10 Pro allows only 1 active session). Error 0x904 occurs when trying to reconnect to a disconnected session that is locked or in a bad state.
This error typically presents the message: "This computer can't connect to the remote computer. Try connecting again. If the problem continues, contact the owner of the remote computer or your network administrator."
Parting practical tip If you need one immediate move when you see 0x904/0x7: confirm TCP 3389 connectivity (Test-NetConnection or telnet) and then check server Event Viewer logs at the exact connection timestamp — those two steps resolve the issue in the majority of cases. Press Windows Key + R