Suppression list
The suppression list protects your sender reputation: Frontmail refuses to send to addresses that bounced hard, complained, or that you blocked manually. Each organization has its own list in Suppressions (in the Audience group of the dashboard menu). Every member can see it; owners, admins and developers can add and remove addresses.
How addresses get on the list
Section titled “How addresses get on the list”| Reason (dashboard label) | Source |
|---|---|
hard_bounce (Hard bounce) |
The provider rejected the address permanently while sending, or a provider webhook reported a permanent bounce (mailbox doesn’t exist, domain invalid). |
complaint (Spam complaint) |
A provider webhook reported that the recipient marked your email as spam (feedback loop). |
manual (Manual) |
You added it in the dashboard with Suppress an address → Add. |
Entries created from a message link to it (Message), so you can see which email bounced. Complaints and most bounces are only detected if you set up delivery webhooks for your service – see the provider guides.
What happens on send
Section titled “What happens on send”If any recipient (To, CC or BCC) is suppressed, the API rejects the request with
451 recipient_suppressed. No credit is used. The
response tells you which address is suppressed; don’t show it to end users verbatim if it could
leak someone else’s address.
Removing an address
Section titled “Removing an address”Click the remove icon next to the entry and confirm Remove. Only do this if you know the address is valid now (e.g. the person fixed their mailbox) or the complaint was a mistake – sending repeatedly to bouncing or complaining addresses can get your provider account suspended.
Adding and removing entries is recorded in the audit log.