This directly addresses ERROR_ARENA_TRASHED .

Verify basic TCP reachability to rule out firewalls:

: On the host machine, administrators should check the Certificates (Local Computer) snap-in. Deleting an expired Remote Desktop certificate and restarting the TermService (Remote Desktop Services) will force Windows to generate a fresh, valid certificate.

In the modern era of distributed workforces and cloud-based infrastructure, the Remote Desktop Protocol (RDP) serves as a critical gateway, allowing users to cross vast digital distances to control a machine as if they were sitting in front of it. However, this gateway is not without its sentinels. Few experiences are as frustrating as being locked out of your own remote machine by an opaque alphanumeric code. Among the many RDP error messages, the combination of with Extended Error Code 0x7 stands out as a particularly vexing barrier. While the primary code indicates a licensing or security-related failure, the extended code reveals a more fundamental problem: the abrupt termination of the network conversation. Together, they tell a story of a connection that is not merely unauthorized, but actively severed during the handshake process.