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Codex "Error submitting message": What It Means and How to Fix It

Codex shows "Error submitting message"? What each version means (thread not found, project root), the fixes from OpenAI's GitHub issues, and when to wait.

By Engineer Foodie Desk Nov 3, 2026 ✓ Sources checked Nov 3, 2026

7 min read

Error wording checked Nov 3, 2026 in OpenAI’s official Codex GitHub repo: #54361, #50178, #49497, #35409, #35388 and #34937. Recovery steps checked Nov 3, 2026 in OpenAI’s Codex troubleshooting page and cloud environment docs. Every source is listed at the bottom. No affiliate links on this page (how we work).

Here’s the short version. “Error submitting message” is a wrapper, not a diagnosis. The useful part is whatever comes after it. In OpenAI’s GitHub issues it shows up in three versions, and they have three different fixes. Thread not found usually clears with a full app restart. Unable to determine project root for task is a Codex Web and cloud-environment problem with no confirmed fix from OpenAI as of Nov 3, 2026. The bare version with no suffix usually means the chat’s agent died, so restart and start a fresh chat.

OpenAI’s docs don’t have an entry for this error as of Nov 3, 2026. Every cause below is labeled with the issue it came from.

The exact error: `Error submitting message`

The bare form, as reported in #35388 (macOS, Plus): every prompt showed “Thinking” and then immediately:

Error submitting message.

The versions people search for, word for word from the issue titles:

Error Submitting Message: Thread not found

Error submitting message "Unable to determine project root for task"

One-line answer: Codex accepted your text but couldn’t hand it to a working thread. Read the suffix, then use the matching fix below. Searching OpenAI’s repo turns up 87 issues containing “Error submitting message” as of Nov 3, 2026, so you have plenty of company.

Error submitting message, by suffix

“Thread not found” (#54361)

#54361 was opened Oct 15, 2026 on Windows (Plus) and is labeled as a session bug in the desktop app. The app is trying to post into a thread it can no longer find. The fix in the thread is short: “restarting codex helped” (comment from Oct 21, 2026).

A close cousin is #35409, titled “Thread “go missing” - Error submitting Message” (macOS, Pro): “Was working fine and then it stopped accepting messages.” It’s The Leftovers for chats. The thread is gone, nobody explains where it went, and you’re left talking to the empty chair.

“Unable to determine project root for task” (#50178, #49497)

This is the cloud one. #49497 describes it on Codex Web: the first message fails “despite runnable cloud environment”. Reporters said a hard refresh and reselecting the environment didn’t help. Follow-up messages failed too, and more than 20 comments with the same failure piled up between Sep 30 and Oct 4, 2026. The issue also links a Windows desktop report (#38325) where the same error showed up during a Local-to-Cloud handoff.

In #50178, environment setup first failed with “Setup is blocked by a cloud provisioning failure: executor_registration_failed”. After that, every message hit the project-root error.

What people tried in #49497, with how it went:

Delete the environment and recreate it in the Mac app. One user said this worked in the Mac app but the browser still failed: “it is broken codex cloud web”.
The workaround OpenAI Support gave one user. “create a fresh cloud environment and send the desired branch/app-root instruction as the first message in the setup conversation”. For that user, setup then sat for 24 minutes on “Task creation is not yet confirmed. Do not submit it again while Codex checks its outcome”.

No OpenAI staff reply appears in #49497 as of Nov 3, 2026. That’s a thread full of paying users doing QA for free. It’s frustrating to see a cloud feature break on the first message and then get support-desk advice that doesn’t hold up in public.

Bare “Error submitting message” (#35409, #35388, #34937)

#34937 (Windows, Pro) gives the clearest picture. The chat sat waiting for the user’s input, and when the user came back, a red toast appeared:

Error creating chat
failed to start turn: internal error; agent loop died unexpectedly

After that, every message in the chat showed “Error submitting message”. In the reporter’s words, “This will repeat for every message in the chat until the app is restarted. Other chats continue to work”. A second reporter tied it to Codex’s built-in Browser tool and said “A full quit and relaunch is the only observed recovery”.

How to fix Codex “Error submitting message”

In order:

Fully quit and relaunch the app. Closing the window isn’t enough. This is the reported fix for Thread not found (#54361) and for the dead agent loop (#34937). OpenAI’s troubleshooting page says that if a chat stays stuck, “wait until your active chats are complete and restart the app” (troubleshooting).
Start a new chat. Per #34937, other chats keep working when one is broken. OpenAI’s troubleshooting page suggests you “Start a new chat with a smaller, more focused prompt”. Copy your prompt out of the broken chat first.
Check for a pending approval. The troubleshooting page says to check whether Codex is waiting for you to approve something. In #34937, the breakage started after an interactive prompt went unanswered.
For project-root errors, republish the cloud environment. OpenAI’s cloud docs say that when setup fails, “select Try again”, then publish or republish after fixing it (cloud environments). If you hit executor_registration_failed first, as in #50178, that’s on OpenAI’s provisioning side. Retrying a few times won’t change that.
Try a different surface. In #49497 the Mac app worked when the browser didn’t. Using the app to keep working is fair game.
Check status.openai.com. If lots of people hit it at once, waiting is the fix.
Send feedback with a session ID. In the desktop app, type / in the composer to send feedback. You get a session ID to add to a GitHub issue. On macOS, logs are in ~/Library/Logs/com.openai.codex/YYYY/MM/DD and sessions in ~/.codex/sessions (troubleshooting).

Mr. Robot said control is an illusion. In this case, so is the send button.

Is it a usage limit instead?

Probably not. Codex’s usage-limit message uses different words: You've hit your usage limit. Try again later. (#57655, verified Oct 30, 2026). OpenAI also says “Starting a new chat does not reset your usage limits”. You can check what’s left with /status in the CLI (OpenAI Help, verified Nov 1, 2026). If you see the usage wording instead, go to Codex usage limit reached.

Which version you have

Suffix	Where	Fix
Thread not found	Desktop app	Full restart
Project root	Codex Web	Rebuild env
Agent loop died	Desktop app	Restart, new chat
Bare message	Any	New chat, status

Here’s what I’d do

Copy your prompt somewhere safe. Quit Codex completely, reopen it, and paste the prompt into a new chat. That clears most of the desktop reports above. If the suffix says project root and you’re on Codex Web, try the same task from the desktop app. Rebuild the environment once, and if it still fails, add your session ID to #49497 instead of re-sending ten times.

If the chat failed even earlier, at the “start” step, see Codex error creating task. Mid-response drops are covered in Codex stream disconnected. If you’ve had enough, Codex alternatives and AI coding tools compared are where to look next.

If the CLI shows turn/start failed in TUI rather than this message, see Codex turn/start failed.

Can’t open the thread at all (“Error loading messages”) rather than failing to submit? See Codex Error Loading Messages.

FAQ

What does Error submitting message mean in Codex? Codex couldn’t hand your message to a working thread; the text after the error (Thread not found, project root, or none) tells you which fix to try.

How do I fix Codex thread not found? Fully quit and relaunch Codex, then continue in a new chat if the old one stays broken; a restart is the fix reported in GitHub issue 54361.

Does a failed message use Codex credits? Not published; OpenAI’s help pages don’t say whether a message that fails to submit counts against your Codex usage or credits.

Why does Codex say Unable to determine project root for task? It’s a Codex Web and cloud-environment failure reported in GitHub issues 49497 and 50178, and OpenAI hasn’t published a confirmed fix as of Nov 3, 2026.

Is Error submitting message a usage limit? No, Codex’s usage limit has its own message, You’ve hit your usage limit, and you can check what’s left with /status in the CLI.

Sources

OpenAI Codex GitHub issue #54361, “Error Submitting Message: Thread not found”: https://github.com/openai/codex/issues/54361 (verified 2026-11-03)
OpenAI Codex GitHub issue #50178, “Error submitting message “Unable to determine project root for task"": https://github.com/openai/codex/issues/50178 (verified 2026-11-03)
OpenAI Codex GitHub issue #49497, “Codex Web: first message fails with “Unable to determine project root for task” despite runnable cloud environment”: https://github.com/openai/codex/issues/49497 (verified 2026-11-03)
OpenAI Codex GitHub issue #35409, “Thread “go missing” - Error submitting Message”: https://github.com/openai/codex/issues/35409 (verified 2026-11-03)
OpenAI Codex GitHub issue #35388, “Error submitting message”: https://github.com/openai/codex/issues/35388 (verified 2026-11-03)
OpenAI Codex GitHub issue #34937 (agent loop died, Error creating chat): https://github.com/openai/codex/issues/34937 (verified 2026-11-03)
OpenAI Codex docs, troubleshooting: https://learn.chatgpt.com/docs/reference/troubleshooting.md (verified 2026-11-03)
OpenAI Codex docs, cloud environments: https://learn.chatgpt.com/docs/environments/cloud-environments.md (verified 2026-11-03)
OpenAI Codex GitHub issue #57655 (usage limit wording): https://github.com/openai/codex/issues/57655 (verified 2026-10-30)
OpenAI Help, using Codex with your ChatGPT plan: https://help.openai.com/en/articles/11369540-using-codex-with-your-chatgpt-plan (verified 2026-11-01)
OpenAI status page: https://status.openai.com (checked 2026-11-03)

The exact error: Error submitting message