OpenAI ChatGPT Pro/Plus browser login fails with `Token exchange failed: 403` on macOS

[XuanningZhang]

Description

Summary

OpenCode fails to complete OpenAI authentication via OpenAI -> ChatGPT Pro/Plus (browser).

The browser authorization flow appears to complete, and the local OAuth callback server starts correctly on localhost:1455, but token exchange fails with:

Token exchange failed: 403

As a result, no OpenAI credential is written to the local auth file.

---

Environment

• OpenCode version: 1.2.19
• OS: macOS
• Installation method: Homebrew CLI
• Running locally on desktop (not SSH / remote / container / WSL)

---

What I did

1. Installed / upgraded OpenCode CLI
2. Ran:

opencode auth login

3. Selected:

   • Provider: OpenAI
   • Login method: ChatGPT Pro/Plus (browser)

4. Completed authorization in browser

---

Expected behavior

After browser authorization, OpenCode should exchange the authorization code for tokens successfully and write the OpenAI credential locally.

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Actual behavior

OpenCode waits for authorization, then fails with:

Error: Unexpected error, check log file for more details

Token exchange failed: 403

No OpenAI credential is added to the local auth file.

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Relevant log output

INFO  service=plugin.codex port=1455 codex oauth server started
ERROR service=default name=Error message=Token exchange failed: 403 stack=Error: Token exchange failed: 403
    at exchangeCodeForTokens (src/plugin/codex.ts:125:15)
    at processTicksAndRejections (native:7:39) fatal

Full log excerpt:

INFO  2026-03-06T05:06:52 +598ms service=default version=1.2.19 args=["auth","login"] opencode
INFO  2026-03-06T05:06:52 +1ms service=default directory=<REDACTED_HOME> creating instance
INFO  2026-03-06T05:06:52 +0ms service=project directory=<REDACTED_HOME> fromDirectory
INFO  2026-03-06T05:06:52 +0ms service=db path=<REDACTED_HOME>/.local/share/opencode/opencode.db opening database
INFO  2026-03-06T05:06:52 +16ms service=db count=6 mode=bundled applying migrations
INFO  2026-03-06T05:06:52 +233ms service=config path=<REDACTED_HOME>/.config/opencode/config.json loading
INFO  2026-03-06T05:06:52 +1ms service=config path=<REDACTED_HOME>/.config/opencode/opencode.json loading
INFO  2026-03-06T05:06:52 +5ms service=config path=<REDACTED_HOME>/.config/opencode/opencode.jsonc loading
INFO  2026-03-06T05:06:52 +23ms service=plugin name=CodexAuthPlugin loading internal plugin
INFO  2026-03-06T05:06:52 +0ms service=plugin name=CopilotAuthPlugin loading internal plugin
INFO  2026-03-06T05:06:52 +0ms service=plugin name=gitlabAuthPlugin loading internal plugin
INFO  2026-03-06T05:06:52 +0ms service=plugin path=opencode-anthropic-auth@0.0.13 loading plugin
INFO  2026-03-06T05:06:52 +25ms service=plugin path=file://<REDACTED_HOME>/.config/opencode/plugins/usage-telemetry.ts loading plugin
INFO  2026-03-06T05:07:04 +11621ms service=plugin.codex port=1455 codex oauth server started
ERROR 2026-03-06T05:08:06 +61623ms service=default name=Error message=Token exchange failed: 403 stack=Error: Token exchange failed: 403
    at exchangeCodeForTokens (src/plugin/codex.ts:125:15)
    at processTicksAndRejections (native:7:39) fatal

---

Auth file state

The local auth file is not updated with any OpenAI credential after the flow completes.

Current contents only show another provider entry, for example:

{
  "minimax-cn-coding-plan": {
    "type": "api",
    "key": "REDACTED"
  }
}

---

Additional notes

• localhost:1455 is listening correctly during the flow
• This is not caused by an outdated CLI version
• This is not a remote environment issue
• Browser authorization appears to succeed, but token exchange returns 403
• Happy to test a patched build or provide more logs if needed

Plugins

Internal auth plugins plus: - opencode-anthropic-auth@0.0.13 - usage-telemetry.ts The issue is specifically with OpenAI -> ChatGPT Pro/Plus browser auth.

OpenCode version

1.2.19

Steps to reproduce

1. Install or upgrade OpenCode CLI to v1.2.19.
2. Run opencode auth login.
3. Select provider: OpenAI.
4. Select login method: ChatGPT Pro/Plus (browser).
5. Complete authorization in the browser.
6. Return to the terminal and observe the error: Token exchange failed: 403.
7. Check local auth state: no OpenAI credential is written to the auth file.

Screenshot and/or share link

No response

Operating System

macOS 26.3.1

Terminal

Terminal.app

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• OpenAI ChatGPT Plus OAuth Token Exchange Failed with 403 #14705: Same exact error — ChatGPT Plus/Pro OAuth browser login fails with Token exchange failed: 403, same flow (browser redirects to localhost:1455, credentials not saved). This issue was previously closed; it may have been resolved or may have regressed.
• OpenAI ChatGPT Pro/Plus (browser) cant be connected, Failed to start server. #14276: Related — ChatGPT Pro/Plus (browser) connection failure at port 1455 during the same OAuth flow (different error, same feature area).

If your issue is the same as #14705, please comment there or reference it so maintainers can track the regression.

[XuanningZhang]

I checked both linked issues.

• OpenAI ChatGPT Plus OAuth Token Exchange Failed with 403 #14705 appears to match my case very closely, but it was closed without a clear technical fix or documented resolution steps.
• OpenAI ChatGPT Pro/Plus (browser) cant be connected, Failed to start server. #14276 seems to be a different failure mode: browser OAuth server startup / port 1455 startup failure. In my case, the local OAuth server starts correctly and browser auth appears to succeed.

So this issue seems closer to #14705 and may be a regression or an unresolved variant rather than the server-startup issue from #14276.

Happy to test a patch or provide any additional logs if helpful.

[XuanningZhang]

Update: I found this was mainly a network issue. After switching to a VPN node with low latency and low packet loss, the ChatGPT Pro/Plus browser auth started working again.

It would be helpful if OpenCode could handle this more robustly (e.g., retries/backoff or clearer error messaging), so it’s less sensitive to transient network/VPN conditions.

[fastknifes]

How to resolve this issue?

[XuanningZhang]

This might be related to network instability, especially when using a VPN.

When the error happened on my side, I noticed that even logging into the OpenAI website sometimes required retries. After login succeeded, the OAuth flow in OpenCode still returned Token exchange failed: 403.

After switching to a VPN node with lower latency and packet loss, the OpenAI login worked without retries and the OpenCode browser auth flow completed successfully.

So it might be worth checking your network connection to OpenAI, particularly your VPN node or connection stability.

[fastknifes]

确实是网络的问题。解决方案：https://blog.csdn.net/m0_63460124/article/details/157400240

[XuanningZhang]

Got it, thanks.