I ran into a strange issue while establishing an RDP connection to a Windows Server 2019 RDS host from Windows 11 via VPN.
After successfully connecting to a Remote Desktop session on Windows Server, the Remote Desktop Connection client (mstsc.exe) closed after 5-10 minutes with the error:
This session will be terminated due to a data encryption error. Try reconnecting to the remote computer.
Error code: 0xc06
To solve an RDP encryption issue, check the following in sequence:
- Install the latest Windows updates through Windows Update;
- Disable the Large Send Offload option in the network adapter settings on the client: open the Device Manager (
devmgmt.msc), expand the Network adapters section, open the properties of your network adapter, and go to the Advanced tab. Change Large Send Offload to Disabled;
- Disable the Link-Layer Topology (Mapper I/O Driver and Responder) and QoS Packet Scheduler protocols in the properties of the network adapter;
- Try to uninstall third-party VPN clients on Windows (Sonicwall Global VPN, OpenVPN client, etc.);
- Update network adapter drivers;
- Reset the Windows network stack:
ipconfig /flushdns netsh int reset all netsh int ip reset netsh winsock reset - Open the Registry Editor and go to the key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TermService\Parameters. Back up this branch (by exporting it to *.REG file) and remove the parameters “Certificate”, “X509 Certificate”, and “X509 Certificate ID”. Then restart your computer.