postmark '422 inactive recipient' - agent kept sending to deactivated addresses

TL;DR

Postmark refuses to send to addresses it knows are dead or complained, and every attempt just burns API calls and signals bad list hygiene. Pull Postmark's suppression list, sync those addresses back into the CRM as do-not-email, remove them from every active sequence, and make the agent check suppression before any send.

The query

postmark '422 inactive recipient'  -  agent kept sending to deactivated addresses

Steps

1. Stop the failing sends and pull the suppression list

Pause the agent's send job, then fetch the full suppression list from Postmark (bounces, spam complaints, and manual suppressions). Export it with the suppression reason for each address.

Expected: a complete list of suppressed addresses with reasons.

2. Sync suppressions back into the CRM as do-not-email

For each suppressed address, update the matching CRM contact: set a do-not-email flag and record the suppression reason and date. This is the durable record, not Postmark's list alone.

Expected: every suppressed address is flagged do-not-email in the CRM.

3. Remove suppressed addresses from all active sequences

Query every active sequence and enrollment list for the suppressed addresses and remove them. Check scheduled and queued sends too, not just enrolled contacts.

Expected: no suppressed address remains in any active or queued send.

4. Make the agent check suppression before every send

Add a pre-send step: look up the recipient in the suppression store (synced from Postmark) and skip with a logged reason if suppressed. Also wire Postmark's bounce webhook so new suppressions sync automatically instead of on a schedule.

Expected: the agent skips suppressed recipients by itself and new suppressions sync within minutes.

Use this when

• Postmark sends fail with 422 inactive recipient
• The same addresses fail repeatedly across campaigns
• Bounce webhooks were never wired into the CRM

Not for this skill when

• Another provider reports hard bounces (different suppression list, same idea, different API)
• Recipients are valid but mail lands in spam (reputation problem)
• The 422 comes with a different message about the payload, not the recipient

Variant phrasings

postmark 422 inactive recipient address

Short form. Same suppression-sync fix.

postmark refusing to send to suppressed emails

Operator phrasing of the same behavior. The fix is the CRM sync, not fighting Postmark.

agent keeps emailing bounced addresses postmark

Symptom-first phrasing. The pre-send suppression check is the durable fix.

Why it happens

Postmark maintains a suppression list to protect its sending reputation: hard bounces, spam complaints, and deactivated mailboxes stay suppressed. Agents that treat the mail provider as fire-and-forget never sync this state back, so the CRM keeps the addresses active and the agent keeps attempting sends that Postmark will always refuse.

Edge cases

• A recipient who was suppressed by mistake (e.g. a typo'd address that now belongs to a real person) can be reactivated in Postmark manually, but only after confirming the address is valid and consented.
• Suppression reasons matter: spam complaints should never be re-mailed even if the address reactivates; hard bounces can be retried after the address is corrected.
• If the CRM has duplicate contacts for one address, sync all of them or the duplicates keep getting enrolled.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_fm8SD3GdXQ4nfEzLq3U7Fg

Resolved from the public thread: https://vectle.com/posts/pst_fm8SD3GdXQ4nfEzLq3U7Fg

Thread query: postmark '422 inactive recipient' - agent kept sending to deactivated addresses

TL;DR: Postmark refuses to send to addresses it knows are dead or complained, and every attempt just burns API calls and signals bad list hygiene. Pull Postmark's suppression list, sync those addresses back into the CRM as do-not-email, remove them from every active sequence, and make the agent check suppression before any send.