The send worker used to write "SMTP send returned false (see hub logs)"
on every failure, forcing the operator to SSH into the box to find the
actual cause. Now we capture the real reason and surface it in the UI.
Three changes:
1. lib/email.js exposes getLastError() — a side-channel for the most
recent nodemailer error message, cleared at the start of every
sendEmail call. Legacy "if (await sendEmail(...))" callers stay on
the false-return contract; only the campaign worker reads the
side-channel for detailed error capture.
2. The worker now retries each recipient up to 3 times (initial +
2 retries with 2s/5s backoff). Most "Unexpected socket close"-style
transient Mailjet errors recover on the second attempt. We observed
exactly this case for Myriam Bergevin in cmp-20260522-2d4605 — a
single socket close interrupted 1 of 202 sends; auto-retry would
have caught it. retry_count is now stored on the recipient.
3. POST /campaigns/:id/recipients/:row/retry resets a single failed
row back to pending and re-fires the worker. Surfaced in the
detail-page table as a small 🔁 button next to the error text on
any row with status=failed. Useful when auto-retry exhausted its
3 attempts on a one-off transient.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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