Suppressions

You do not maintain a suppression list by hand. An address is added to the suppression list automatically the moment it hard bounces, draws a spam complaint, or a recipient unsubscribes, and every send after that skips the address. Suppression protects your sending reputation and keeps you compliant: it works in the background, with no toggle to flip and no list to curate.

What gets an address suppressed

Three things suppress an address, each recorded with a reason:

Reason	Triggered by	Recorded as
Hard bounce	The mailbox does not exist, or permanently rejected the message	hard_bounce
Complaint	The recipient marked your email as spam in their inbox	complaint
Unsubscribe	The inbox one-click unsubscribe or the footer unsubscribe link	unsubscribed

Soft bounces, temporary failures such as a full mailbox or a server that is briefly unreachable, do not suppress. They are acknowledged and the address stays eligible for your next send.

Suppression is account-wide

A suppression is keyed to your account and the email address, with one record per address. Because the suppression list belongs to your Mercleo Account rather than to a single product, an address suppressed through a campaign is also suppressed for email sent through Events and Reach on the same account. One unsubscribe or one hard bounce covers every product you send from.

If the suppression list cannot be read at send time, the batch does not send at all rather than risk mailing a suppressed address: the check fails closed.

Marketing vs transactional enforcement

Each campaign is sent as Marketing or Transactional, chosen on the campaign's email-type field. The field's helper text states: "Marketing emails honor unsubscribe and suppression. Transactional emails are operational messages."

Marketing campaigns also skip any contact whose marketing opt-in is not explicitly on, separately from the suppression list. The suppression check, by contrast, applies regardless of email type: a suppressed address is never delivered to, even on a transactional send.

Suppressions also exit journeys

A hard bounce or complaint that suppresses an address also hard-exits every active journey enrollment for that contact, on top of the suppression itself. An unsubscribe does the same at the moment it happens. A contact who triggers a suppression stops moving through any journey they were enrolled in, not just future campaign sends.

Where you see suppression in a campaign

There is no standalone suppression-list screen. Suppression surfaces inside the campaign itself. When a campaign sends, any recipient whose address is suppressed is marked with the Suppressed status in the Recipients table on the campaign detail page. The Delivery metrics row above the table summarizes Sent, Delivered, Unique opens, Unique clicks, and Bounced; read the per-recipient Status column to see which addresses were skipped as suppressed.

A suppressed recipient is a skipped send, not a delivery error. The address is left out of the send and the row carries a last error noting the recipient is suppressed; nothing about your campaign needs fixing. If a campaign resolves to recipients who are all suppressed or all failed, the campaign finishes with a Failed status even though no send error occurred.

Lifting a suppression

There is no operator screen to browse the suppression list or lift a suppression, and re-sending a campaign does not reach a suppressed address. An unsubscribe or a complaint is the recipient's choice; a hard bounce means the mailbox is gone. In each case the right outcome is to stop sending, which is what suppression does.

The only way a suppression comes off is the recipient lifting it themselves, from the preference centre linked in your email footer, which has a re-subscribe toggle that removes the address from the suppression list. That toggle clears whatever suppression is on the address, not only the unsubscribe reason, but the recipient can act on it only through a preference-centre link they already hold, since a suppressed address receives no new mail. See Unsubscribing for that flow from the recipient's side.