OpenAI Codex Phone Verification: Why Your Number Gets Rejected (and the Real-SIM Fix That Works)
You installed Codex, ran codex login — and hit a wall: phone verification required. Even though your ChatGPT account never asked for one. You enter your number… and get "VoIP not supported" or the code never arrives.
You're not alone — Codex's SMS step-up is one of the most complained-about issues in OpenAI's GitHub repos. This guide explains why your number gets rejected and the fix that works 99% of the time.
Why Codex is stricter than ChatGPT
Codex CLI triggers an SMS verification step-up even on accounts that verified fine on the web. Worse, Codex permanently locks the verified number to your account — use a disposable number and you may lose the account at the next re-verification. This is not the place for a throwaway number.
Why your number gets rejected: the VoIP wall
Before sending any code, OpenAI checks your number against carrier databases. If the number's line type shows as VoIP, landline, or Google Voice, verification is blocked instantly. That's why:
- Google Voice / TextNow / 2ndLine → rejected ("VoIP not supported")
- Free SMS inbox sites → rejected (recycled numbers are blacklisted, and anyone can read your code)
- Cheap bulk SMS sellers → often VoIP ranges that get flagged
Only numbers showing line_type: mobile — real physical SIM cards — reliably receive the code.
The fix: a real US SIM number (99% success)
The Codex SMS Verification gives you a real physical-SIM US number — the highest-trust number type for OpenAI — delivered instantly with an activation code:
- Buy — $0.50, pay with your TokenLooT balance.
- Get your URL + activation code instantly.
- Open the URL, enter the code — your US number appears.
- Enter it in Codex and request the OTP. It arrives in seconds.
- Done. You only pay when the SMS actually arrives.
Real SIM vs the alternatives
| TokenLooT real SIM | 5sim / SMS-MAN | Free SMS sites | |
|---|---|---|---|
| Line type | ✅ mobile (physical SIM) | ⚠️ often VoIP | ❌ blacklisted |
| Codex success | ✅ 99% | ⚠️ inconsistent | ❌ ~0% |
| Speed | ✅ seconds | ⚠️ delays reported | — |
| Price | ✅ $0.50 | $1–$4+ | free (doesn't work) |
A warning about disposable numbers and Codex
Because Codex permanently binds your verification number, a number you can't recover is a liability. Keep your activation details safe — if Codex ever re-verifies, you'll want the same number.
Frequently asked questions
Why does OpenAI say my number is VoIP?
OpenAI queries carrier databases for the number's line type. Virtual numbers from apps like Google Voice or TextNow register as VoIP and are rejected before any SMS is sent.
Can I verify Codex from Pakistan or India?
Yes. A US number carries the highest OpenAI trust regardless of your location. Just avoid obvious geo-mismatch signals during signup.
What if the OTP doesn't arrive?
You only pay when the SMS arrives — failed attempts cost nothing, and you can generate a new number.
Stuck on verification? Get your real US SIM number now and verify Codex in under a minute.
