Windows Codex Remote Control fails to enable / pairing times out despite single instance and successful remoteControl/enable response

Environment:

• Windows x64
• OpenAI.Codex version: 26.911.7940.0
• Single OpenAI.Codex AppX installation
• Only one ChatGPT/Codex main application instance is running

Problem:
Remote Control cannot be enabled reliably on Windows.

Symptoms observed:

1. Clicking Settings > Connections > Control this computer > Allow often shows:
   "Unable to enable remote control. Please try again."

2. At one point it also showed:
   "Please ensure only one ChatGPT/Codex instance is running."

3. After repair/re-login, the UI sometimes progresses to the pairing screen, but then fails with:
   "Timed out waiting for remote control to connect"

4. The QR/pairing code cannot be obtained reliably.

Troubleshooting already performed:

• Fully restarted Windows
• Ended ChatGPT/Codex processes and reopened only one instance
• Verified there is only one OpenAI.Codex AppX package installed
• Verified the multiple ChatGPT.exe processes are child renderer/GPU/network processes under one main process
• Windows App Repair completed successfully
• Signed out and signed back in
• Retried Remote Control multiple times
• Cleared/renamed Codex plugin cache
• Tested again after restart
• Issue persists

Relevant process information:

• Main ChatGPT.exe process launches normal child processes
• One codex.exe backend process
• One codex-computer-use-swift.exe helper process
• No second independent Codex/ChatGPT application instance was found

Relevant log entries:

remoteControl/enable returns without an RPC error:

method=remoteControl/enable
errorCode=null

Remote connection refresh completes with zero connections:

refresh_remote_control_started previousConnectionCount=0

reconcile_completed
creationFailureCount=0
nextConnectionCount=0
previousConnectionCount=0

refresh_remote_control_completed
autoConnectConnectionCount=0
nextConnectionCount=0
previousConnectionCount=0

Device attestation repeatedly reports unavailable:

[devicecheck-attestation]
DeviceCheck attestation unavailable
deviceCheckLatencyMs=null
durationMs=0
errorCode=1

The Remote connection state also briefly transitions through connected / connection-failed and then disconnected.

Additional app-server/IPC log entries observed:

ipc-connection-reset

Socket error
errorCode=EPIPE
errorMessage="write EPIPE"

Stopping app-server transport

app_server_connection.state_changed
previous=connected
next=disconnected

Observed behavior:
The desktop client can sometimes reach the Remote Control pairing UI, but the remote connection does not remain established and pairing eventually times out.

Expected behavior:
After clicking Allow, the Windows host should remain connected to Remote Control and generate a pairing code / allow the phone to authorize the computer.

Please investigate Windows Remote Control enrollment / DeviceCheck attestation / app-server connection handling for version 26.911.7940.0.

Start by reproducing the Windows flow around remoteControl/enable and inspect the refresh_remote_control, reconciliation, DeviceCheck attestation, and app-server IPC logs together. Trace the connected-to-disconnected transition and EPIPE reset to determine why pairing does not persist. Done means Allow reliably produces a pairing code and the host remains connected without the timeout.