Suppression
Suppression is the absolute do-not-send list. It is checked before every individual message, whatever the campaign or the topic.
Where to find it
Architect Panel → Commercial:
- Campaign Manager — campaigns the list is applied to
Architect Panel → Activity:
- E-mail Log — sends and their results
Suppression is not a preference
The distinction matters:
- A preference is topic-level and set by the recipient. They still hear from you about other topics.
- Suppression is address-level and absolute. Nothing goes to that address.
Preferences are a choice; suppression is a hard stop, usually created by something going wrong.
How addresses get on the list
- A hard bounce — the address does not exist.
- A complaint — the recipient marked a message as spam.
- A manual addition — somebody asked in writing, or by another route.
Why it protects you
Continuing to send to addresses that bounce, or to people who have complained, is precisely what receiving mail systems use to judge whether you are a legitimate sender.
Suppression is therefore not merely courteous — it is what keeps your messages reaching everybody else. A list allowed to accumulate dead addresses will eventually see all your mail treated as spam, including transactional messages people need.
Suppression applies across channels too
Like preferences, suppression is dual-written, so an address suppressed on one side is suppressed on the other. Somebody who complained about an e-mail does not then receive the same thing by text.
Do not remove entries
The temptation arrives when a valuable customer's address is suppressed and somebody wants to reach them. Resist it.
If they complained, sending again is the worst possible response. If it was a hard bounce, the address does not work and sending achieves nothing while damaging your reputation.
Contact them another way, and get a fresh, correct address from them directly.
The legitimate exception
A confirmed error — the wrong address suppressed through a mistaken bulk action, or somebody who has explicitly asked to be re-subscribed and given you a working address. Both are rare and both should be recorded.
Review the list for what it tells you
A rising suppression rate is a data quality signal. Many hard bounces means your addresses are decaying; many complaints means your content, frequency or audience selection is wrong — and complaints are the more urgent of the two.
Complaints deserve investigation
People who complain generally could have unsubscribed instead. When several do, something about that campaign made unsubscribing feel harder than complaining — an unclear link, an unexpected message, an audience who did not remember opting in.
Worked example
After a campaign, an organisation sees eleven complaints against a usual figure of one or two. The audience turned out to include people who had not heard from them in three years and did not recognise the sender. The list is cleaned to active contacts and a re-permission campaign is sent to the rest — complaints return to normal on the next send.
Recommendations
- Never remove a suppression to reach somebody.
- Treat a complaint spike as urgent.
- Watch bounce rates as a data quality measure.
- Get a fresh address from the person, not from your records.