Hmmm… can't reach this page: I get this after signing in anyone has this issue?

Codex Codex CLI
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3

Got the fix.

How to Fix Codex Sign-In on VS Code with WSL2 (localhost:1455 errors)

I was stuck with ERR_CONNECTION_REFUSED, Invalid Session, and State mismatch errors when trying to sign in to Codex in VS Code with WSL2. After a lot of trial and error, here’s the full solution that worked for me.

Steps

1. Install Firefox inside WSL2

By default, Ubuntu on WSL2 doesn’t ship with a browser. Codex login requires one inside WSL, because the login server listens on localhost:1455 inside WSL only.

Install Firefox via Snap:

sudo apt update
sudo apt install -y snapd
sudo snap install firefox

:warning: Don’t try to use Windows Firefox/Chrome here — they can’t reach WSL’s loopback server without extra networking hacks.

2. Start the Codex login flow

In your WSL2 terminal:

codex auth login

This starts a local server at http://localhost:1455 (inside WSL) and prints a long https://auth.openai.com/... URL.

:warning: Keep this terminal open — if you close it, the login server shuts down.

3. Open the login URL in Firefox (inside WSL2)

Open another WSL2 terminal and run:

firefox "https://auth.openai.com/..."

  • Paste the full URL from the codex auth login output.

  • Quote the URL ("...") so bash doesn’t split on spaces.

  • If you see spaces in the URL (e.g. scope=openid profile email ...), replace them with %20.

This will launch Firefox through WSLg (GUI apps on Windows 11), and the redirect to localhost:1455 will correctly reach Codex’s listener.

4. Complete the sign-in

  • Log into your OpenAI account.

  • Approve access.

  • You should see either:

    • A browser success page: “Signed in to Codex”, or

    • The CLI prints:

      Successfully logged in

If you see “Invalid Session” or “State mismatch”:

  • Don’t reuse old URLs.

  • Restart with a fresh codex auth login.

  • Clear cookies for auth.openai.com in Firefox if needed.

5. Reload VS Code

Back in VS Code (Remote-WSL):

  • Run Ctrl+Shift+P → Reload Window.

  • The Codex extension should now show you as signed in.

If it still says “Sign in with ChatGPT”:

codex auth whoami   # should print your account
codex auth logout
codex auth login    # then redo the Firefox step

Notes

  • If you install Codex extension on Windows VS Code instead of WSL, you must log in on the Windows side (codex auth login in PowerShell/CMD) and may need URL ACLs:

    netsh http add urlacl url=http://localhost:1455/ user=%USERNAME%
netsh http add urlacl url=http://localhost:1455/auth/callback/ user=%USERNAME%

  • For most people, the cleanest way is do everything inside WSL2 using Linux Firefox installed via Snap.

TL;DR

  1. sudo apt install snapd && sudo snap install firefox

  2. Run codex auth login in WSL2 (keep terminal open).

  3. In another WSL2 terminal:

    firefox "https://auth.openai.com/..."

  4. Complete login → see “Signed in to Codex”.

  5. Reload VS Code window.