Why were some contacts skipped from my broadcast?

Because they could not be emailed safely. Before a broadcast sends, Coastline removes five kinds of recipient and shows you the count for each on the first step, so the number on the send button is the number of people who will genuinely receive it.

No email on file. The contact, or the record pointing at the contact, has no email address.

Duplicate. The same contact, or the same address, appeared more than once in your audience. This is common when mailing from a report, where several opportunities can share one customer. They receive one email, not three.

Unsubscribed. They used the unsubscribe link in an earlier email from your workspace. Coastline will not email them again on your behalf, and you cannot override this.

Previously bounced. Mail to that address permanently failed before, usually because it no longer exists. Sending to addresses that are known to be dead is one of the fastest ways to damage your sending reputation, so those are held back.

Missing personalization. The contact has no value for a field you used and you left that field's fallback blank. Adding a fallback brings them back into the audience. See how to personalize a broadcast.

Each skipped recipient is listed on the broadcast with its reason, so you can see exactly who missed out and why. Open the broadcast at Campaigns, Broadcasts and look at the Detail column.

If the skipped count is higher than you expected, the usual cause is a filter that pulled in records without contact details rather than anything wrong with your list. Fix the underlying contacts and send again to the remainder.