Mailjet Account Suspended or Under Review for Bounces: What to Do

If Mailjet suspends or reviews your account for bounces, find the campaign and list that caused the spike, verify and clean the whole contact list, then contact support with a clear explanation of what happened and what you changed. When sending resumes, start with your most engaged contacts at low volume and build back up.

Why email platforms suspend accounts

Mailjet sends for many customers through shared infrastructure. High bounce rates and spam complaints from one account can hurt delivery for others, so platforms watch these numbers and act when they climb. Typical triggers:

• A campaign sent to an old list that has not been mailed in a long time.
• A list imported from another tool that included bounced or unsubscribed contacts.
• A purchased, rented or scraped list.
• A signup form filled by bots.
• A sudden large send from a new account.

Exact thresholds and review processes change, so check Mailjet's current documentation and any message support sent you.

Step 1: Read what support said

Suspension emails usually name the reason: bounces, complaints, a list quality concern, or a request for information. Answer the specific question. If they asked where the list came from, start there.

Step 2: Find the campaign that caused it

In your campaign statistics, look for:

• The campaign with the highest bounce rate.
• Which contact list it went to.
• When that list was last mailed, and where it came from.

Most suspensions trace back to one list or one import. Knowing which one makes your explanation credible.

Step 3: Export bounces and look at the reasons

Export bounced contacts with their bounce reasons. Sort them:

Bounce type	What it means
User unknown, mailbox does not exist	List quality problem
Domain not found	Typos or dead company domains
Mailbox full or temporarily unavailable	Usually temporary; watch for repeat failures
Blocked, policy or spam rejection	Reputation or authentication problem

If most bounces are "user unknown", the list is the problem and verification is the fix. If most are blocks, also check authentication and content. The bounce message analyzer helps classify pasted bounce text.

Step 4: Verify the entire contact base

Export all contacts, not just the list that caused the problem. Other lists may be in similar shape. The verify page splits them into:

Result	Action
Valid	Keep
Catch-all	Keep, send after valid contacts
Risky or unknown	Hold; re-check later
Disposable	Remove unless they are recent, engaged customers
Invalid	Remove

Also remove anyone who did not opt in. Verification cannot fix permission problems: a valid address that never asked for your email is more likely to report spam.

Step 5: Fix the source

If the problem came from a signup form, add protection so it does not happen again: real-time verification at signup, double opt-in, or a honeypot field. How to stop fake signups covers these. If it came from an old list, decide whether to send a re-permission email or drop the oldest contacts entirely.

Step 6: Respond to support

A good response is short and specific:

1. What happened: "Campaign X went to a list last mailed in 2024."
2. Where the contacts came from and how they opted in.
3. What you did: verified all contacts, removed a stated number of invalid and risky addresses, removed contacts without clear opt-in.
4. How you will send now: engaged contacts first, smaller batches, regular verification.

Avoid vague promises. Concrete steps are easier for a reviewer to accept.

Step 7: Restart carefully

When sending is restored:

• Send first to contacts who opened or clicked recently.
• Keep volumes modest for the first few campaigns.
• Check bounces and complaints after every send.
• Add older segments only once the numbers look healthy.

Make sure your domain is authenticated in Mailjet with SPF and DKIM, and that you have a DMARC record. The bulk email authentication checker checks the DNS side.

How to avoid a repeat

Habit	Why
Verify before every large send	Lists decay monthly
Verify at signup	Stops typos and fake addresses at the door
Sunset unengaged contacts	Reduces complaints and dead addresses; see sunset policies
Never import purchased lists	They break platform rules and produce bounces and complaints
Watch each campaign's bounce rate	Catch problems on the first send, not the fifth

If you are thinking of switching platforms

Moving to another platform without fixing the list just moves the problem. Most platforms have similar rules, and a new account has less trust than an old one. Clean the list first, whatever you decide. Verify your list before switching ESPs covers migrations.

Worked example (illustrative)

An online course business imports 15,000 contacts collected over five years and sends a promotion to all of them on a new Mailjet account. Bounces climb past 9% within an hour and sending is paused.

• The bounce export shows most failures are "user unknown" and "domain not found", which points at list age rather than content.
• The full contact base is verified. Suppose around 1,800 come back invalid and 600 disposable; both groups are removed, along with 900 contacts with no record of opting in.
• The reply to support explains the source, the cleaning steps and the plan: engaged contacts first, batches of 2,000, verification before every campaign.
• After reinstatement, the first send goes to 3,000 recently active contacts. Bounces stay under 1%, and the remaining segments follow over two weeks.

Clean the list before you appeal

Upload your full Mailjet export on the verify page. You get 100 free email checks when you sign in with Google, no card. For larger contact bases, monthly plans are on the pricing page.