# X_MAIL_CREDENTIAL_MISSING

## Means

this deployment configured no mail transport

## Typical cause

neither `SMTP_URL` nor `RESEND_API_KEY` is set outside `development`/`test`, so `selectMailDriver` installed a driver that refuses. The memory driver used to be installed there instead and reported `accepted` for mail that never left the process — password resets, receipts and invitations all "sent", none delivered, no error anywhere

## Fix

set `SMTP_URL="smtps://user:pass@host:465"` (or `RESEND_API_KEY=re_…`) and `MAIL_FROM="App <no-reply@yourdomain.test>"` in the deployment environment, then restart. `X_MAIL_DRIVER_UNAVAILABLE` is the other half: that one is no driver installed — no `mail:` in `apps/<app>/runtime.ts` and no transport variable

[Mail](/error-codes#mail)