Long-time OpenAI user (since 2023) suddenly required to verify phone number in Codex

What version of the Codex App are you using (From “About Codex” dialog)?

26.519.41501 (3044)

What subscription do you have?

Free

What platform is your computer?

Darwin 23.5.0 arm64 arm

What issue are you seeing?

I have been using OpenAI since February 2023 and have previously used the standalone Codex app without any phone verification.

Recently, after logging out and logging back in, Codex started requiring phone verification before I could continue using the app.

My OpenAI account is not a new account. I can confirm account activity dating back to February 2023.

The problem is that valid Chinese mainland phone numbers (+86) are rejected immediately with the error:

"The phone number you entered is invalid. Please check and try again."

The error occurs before any SMS verification code is sent.

Questions:

Why are long-time Codex users suddenly required to verify a phone number?
Is this expected behavior or part of a rollout?
Are Chinese mainland (+86) phone numbers currently supported for Codex verification?

Additional information:

Subscription: Free
ChatGPT works normally
Issue only affects the standalone Codex app
Previously able to use Codex without phone verification

Thank you.

What steps can reproduce the bug?

Open the standalone Codex app.
Sign in with an existing OpenAI account.
Codex requests phone number verification before allowing access.
Select China (+86) as the country code.
Enter a valid Chinese mainland mobile phone number.
Click Continue.

Result:

Codex immediately displays:

"The phone number you entered is invalid. Please check and try again."

The error occurs before any SMS verification code is sent.

What is the expected behavior?

Expected behavior:

Users with long-established OpenAI accounts should not be required to complete additional phone verification when logging into Codex, especially if they have previously used Codex successfully.

If phone verification is necessary for security reasons, it would be reasonable to exempt trusted accounts, such as:

Long-time OpenAI users with a history dating back several years
Paying subscribers (Plus, Pro, Team, or Enterprise)
Users who already have other security measures enabled

At a minimum, Codex should clearly explain why phone verification is required and which phone number regions are currently supported.

Additional information

_No response_