Writing the Reply to an ESP Account Review or Suspension: Cause, Changes Made, How They Prevent a Repeat

Finish the cleanup first, then write three short paragraphs: what caused it (one specific source, with dates), what you've already changed (with numbers), and how those changes stop it happening again. Leave out anything you haven't done yet. Amazon SES says so explicitly, and HubSpot only lets you submit once.

The ESP suspension appeal builder writes the reply from what you tick and flags anything that weakens it. Sources: the Amazon SES sending review FAQ (read 2 November 2026), HubSpot: resolve email sending suspensions and Mailgun: "Poor mailing list".

What each platform asks for

Platform	Where the reply goes	What it asks for
Amazon SES	Reply to the case in AWS Support Center	Root cause; changes already implemented; how they prevent a repeat. Bounces: how you track them and validate new addresses. Unsolicited mail: how you acquired the list and your opt-in/opt-out links
HubSpot	Marketing > Email > Health > How to Fix	Contacts not emailed in 12 months, contact sources and permission. Once only
Mailgun	Support ticket	How the list was cleaned, how you collect addresses (link the form), what you send, whether it's double opt-in
Brevo	Deliverability Center	Self-service reactivation for a first campaign suspension

Platform walkthroughs: Amazon SES bounce rate review, HubSpot suspension appeal, Mailgun poor mailing list, Brevo campaigns suspended, Klaviyo account under review.

Before you write

1. Find the source. The import, vendor file or segment behind the incident. A per-source breakdown usually shows it: finding which list source caused the bounces.
2. Remove or verify that whole source, not only its bounces. HubSpot notes bounced contacts are already suppressed and removing them alone won't restore sending; SES says removing bounced addresses "without any additional investigation might not solve the underlying problem".
3. Suppress bounces and complaints everywhere you send from.
4. Change the intake. Double opt-in on forms, no bought lists, verification on import. Do it now, so you can list it as done.
5. Write down the numbers: contacts removed, contacts remaining, what was verified and when.

Writing it

• Cause, specifically. "On 28 October we sent a promotion to 21,000 contacts that included a 2023 trade-show import of 3,100 addresses that hadn't been mailed since. Most of the hard bounces came from that import."
• Changes made, with numbers. "We removed the 3,100 imported contacts, verified the remaining 18,000 and removed 410 invalid addresses, and turned on double opt-in for the event form."
• Why it won't recur. "Imports now go through verification before they can be added to a send, and contacts not emailed in 12 months are excluded until they re-confirm."
• Answer every question the notice asks. SES says to provide any information it specifically requests.

What sinks an appeal

Plans instead of changes ("we will clean our list"). Vague causes ("some bad addresses"). Keeping a purchased list and hoping. And, for complaint cases, treating it as a bounce problem: complaints come from real people who didn't want the mail, so the fix is permission, not hygiene. See recovering after sending to a purchased list.

Limits

A well-written reply doesn't guarantee reinstatement, and some suspensions can't be lifted (HubSpot accounts on free tools; a second Brevo campaign suspension). Reviewers can check what you say, so say only what's true.

Where SimpleVerifier fits

Upload the segment behind the incident at /verify so the reply can truthfully say it was verified, with the counts: valid, risky and invalid download separately. The first 100 checks are free with a Google sign-in. Pro is $39 a month with the first 100,000 checks a month at full speed, then slower, never cut off. See pricing.