[BUG] Phone number verification failed

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When activating the Claude account, a user could not verify the phone number because she did not receive any text messages
Phone number: +84 979921423 (country: Vietnam, country code: +84)

<img width="1096" height="624" alt="Image" src="https://github.com/user-attachments/assets/b373c421-6649-4fcc-9023-87f807ff2d20" />

What Should Happen?

Receive the verification code via a text message

Error Messages/Logs

Too many verification attempts. Wait and try again later.

Steps to Reproduce

1. Click on Accept invitation from email
2. Enter the phone number, region = Vietname, phone number = 979921423
3. Click Send verification code
4. No text messages received
5. Try to verify phone number several times

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

web app, the newest version

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_