[BUG] Login verification emails never delivered (ESP suppression list?) — fully locked out of Claude Code on Max plan, recurring issue

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?

Summary

Login verification emails for my account (question@sinfoni.fr) are never delivered.
Our mail gateway logs (VadeSecure) show ZERO inbound SMTP connection attempts from
Anthropic's ESP, while external test emails (Gmail) are delivered instantly to the
same address. The problem is entirely upstream, before delivery to our infrastructure.

This is the second occurrence in a month. Last time, all pending verification emails
were suddenly delivered in a single batch after hours of delay — consistent with a
stuck sending queue or suppression list issue at the ESP level.

Same root cause as #79808.

Impact

• Paid Max plan (90€/month), completely locked out of Claude Code since Aug 20, ~13:00 UTC
• OAuth fallback is ALSO blocked: granting Claude Code access requires a "recent login"

(claude.ai/login?reauth), which itself requires the email code that never arrives —
both in the browser flow and in the desktop app's integrated Code tab

• Active development project fully stalled

Evidence

• VadeSecure gateway logs: no inbound connection from Anthropic/ESP at any code request

timestamp; a Gmail test to the same recipient at 15:52 delivered instantly (screenshots available)

• No blocking, quarantine, or greylisting on our side (verified)
• Support conversation ID: 215475568421462 (escalated to human agent Aug 20, 07:08 PT,

no response yet)

Request

Please check the ESP suppression list / sending queue status for question@sinfoni.fr
and purge whatever is blocking delivery. Given the recurrence, please also identify
why this address keeps falling into this state.

Detailed gateway logs and screenshots are available on request — I have already
provided them in support conversation 215475568421462 rather than attaching them
here, as they contain internal infrastructure details.

What Should Happen?

I should receive my code by mail !

Error Messages/Logs

No mail received
Detailed gateway logs and screenshots are available on request — I have already 
provided them in support conversation 215475568421462 rather than attaching them 
here, as they contain internal infrastructure details.

Steps to Reproduce

Try to login

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Can't kown, can't login !

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

_No response_