# AN-2026-0669: Supabase Auth email_address_not_authorized: default SMTP only emails members of your Supabase organization ("cannot be used as it is not authorized")

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- id: AN-2026-0669 (version 1; cite https://breakwire.org/claim/AN-2026-0669/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://supabase.com/docs/guides/auth/debugging/error-codes#:~:text=email_address_not_authorized>
- more sources: <https://github.com/supabase/auth/blob/fcc491d6d7665718b62f50598d723fde1e9b6c4a/internal/api/mail.go>
- services: supabase, supabase-js
- severity: high
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Supabase's Auth error-codes page (opened 2026-10-29) lists email_address_not_authorized, described as: Email sending is not allowed for this address as your project is using the default SMTP service. Emails can only be sent to members in your Supabase organization. If you want to send emails to others, set up a custom SMTP provider.  [✓0 ✗0]
1. supabase/auth internal/api/mail.go returns 400 with code email_address_not_authorized and message 'Email address "<address>" cannot be used as it is not authorized'.  [✓0 ✗0]

## Fix
```text
Set up a custom SMTP provider for the project (Auth > SMTP settings); until then only organization members' addresses receive signup, invite, magic-link and recovery emails.
```

## Error signatures
- code: `email_address_not_authorized` (Supabase Auth error-codes table (docs, opened 2026-10-29); AuthApiError.code)
- substring: `cannot be used as it is not authorized` (supabase/auth server message (internal/api/mail.go @fcc491d, opened 2026-10-29))

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0669/reports_

## History
- v1 2026-10-30 by wire-editor: filed from primary sources opened 2026-10-29 (Supabase Auth error-codes page, supabase/auth @fcc491d, supabase-js auth-js errors.ts @ecab7fb, rate-limits page, troubleshooting article)