Image uploads fail with connection errors in Codex Desktop and Canva plugin

Start by reproducing the upload failure in Codex Desktop and reviewing the local Codex log database. Trace the reported disconnects through codex_core::responses_retry and codex_app_server_transport::transport::remote_control::websocket, including requests to the listed backend endpoint. Done means identifying the transport failure and verifying that direct image uploads and Canva-plugin uploads complete successfully.

Summary

In multiple conversations in this project, image uploads fail with a connection error. The same behavior occurs when asking Codex to process an uploaded image directly and when using the Canva plugin. Repeating the upload does not resolve it.

Environment

• Codex Desktop: 26.915.31945
• OS: macOS (Apple Silicon; exact macOS version not captured)
• Project: ASHR/2026
• Date observed: 2026-09-20 (Asia/Shanghai)
• Models seen in affected sessions: gpt-5.6-sol, gpt-5.6-luna, gpt-5.6-terra

Steps to reproduce

1. Open a conversation in the project.
2. Attach an image and ask Codex to inspect/process it.
3. Repeat in another conversation through the Canva plugin.
4. Observe that the upload/processing connection fails.

Expected behavior

The image uploads successfully and is available to Codex or Canva for processing.

Actual behavior

The upload/processing connection fails. This reproduces across direct Codex image handling and the Canva plugin.

Sanitized log excerpts

2026-09-20 21:01:37 WARN codex_core::responses_retry
stream disconnected - retrying sampling request (1/5)
sampling_error=stream disconnected before completion:
IO error: peer closed connection without sending TLS close_notify

2026-09-20 21:01:37 WARN codex_app_server_transport::transport::remote_control::websocket
remote control websocket reader disconnected:
failed to read from websocket: IO error: peer closed connection without sending TLS close_notify

2026-09-20 14:42:16 WARN codex_core::responses_retry
stream disconnected - retrying sampling request (5/5)
sampling_error=error sending request for url
(https://chatgpt.com/backend-api/codex/responses)

The excerpts above are from the local Codex log database; paths, account identifiers, and unrelated conversation content were omitted.

Additional context

The failures appear to be transport-level disconnects rather than an image-format-specific error. Please advise whether additional renderer/network diagnostics are needed.