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✉️ Email Delivery

Documentation, reference material and tutorials for CRM-NG SMTP Email: setup guides for every mail service, troubleshooting, and one article per error message.

Error: Email address in suppression list

Updated

By Duane GarnerChief Executive Officer (CEO)
Summarize: Claude ChatGPT View Markdown
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Your mail service refuses to send to a recipient it has blocked after an earlier bounce, complaint or unsubscribe. Check why before removing it.

This article is for sites where a send fails because the recipient is on a suppression list. It is most often reported by the SendLayer mailer, and the same idea applies to other API mailers that keep such lists, including Amazon SES, SendGrid, Postmark, Mailgun, MailerSend, Brevo and SparkPost.

The error as you see it

Email address in suppression list (wording varies: "recipient is suppressed", "address is on the suppression list", "inactive recipient")

Shown in the failed-send banner, in Tools → Debug Events and in the Email Log, for the recipient concerned.

What this error means

Mail services keep a suppression list: addresses they will no longer send to on your behalf. An address is added when an earlier email to it bounced hard (the mailbox does not exist), when the recipient marked your mail as spam, or when they unsubscribed. Sending to those addresses again harms your sender reputation, so the service blocks the message before it leaves. Your settings are fine; the problem is one recipient.

Common causes

  • A hard bounce: the address was mistyped, or the mailbox was closed.
  • A spam complaint: the recipient pressed "Report spam" on an earlier email.
  • An unsubscribe recorded by the mail service.
  • A temporary problem that was recorded as permanent, such as a full mailbox or a receiving server outage at the time of an earlier send.
  • An address that receives only automatic mail (for example an admin address that once rejected mail during a mailbox move).

How to fix

  1. Find the address

    Open CRM-NG SMTP → Tools → Debug Events or the failed email in CRM-NG SMTP → Settings → Email Log and note the recipient.

  2. Open the service's suppression list

    In your mail service's dashboard, find the suppression list. Typical places: SendLayer's suppressions or blocked-recipients page; Amazon SES Configuration → Suppression list in the right region; SendGrid Suppressions (bounces, spam reports, unsubscribes); Postmark the message stream's Suppressions tab; Mailgun the domain's Suppressions. The console's current name may differ slightly.

  3. Read the reason

    Each entry says why and when it was added. If it was a spam complaint or unsubscribe, do not remove it: the person asked not to get your mail.

  4. Correct or confirm the address

    For a bounce, check the spelling with the person, or confirm the mailbox now works (for example, they write to you from it).

  5. Remove the entry

    Only when the cause is fixed, delete the address from the suppression list.

  6. Send a test

    Go to CRM-NG SMTP → Tools → Email Test, enter the address in Send To and press Send Email.

Verify it worked

The test page shows "Test email sent successfully! Check your inbox to confirm delivery." and the recipient confirms they received it.

Notes

  • If many addresses are suppressed, look at where they come from. Bots filling in contact or sign-up forms with fake addresses are a common source; add spam protection to the forms.
  • Password resets and order emails to suppressed addresses will keep failing quietly. Turn on Email Failure Alerts on the Alerts tab so you hear about them.
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