Nothing is dropped silently. Every skipped email is recorded with a reason, so this is a lookup rather than an investigation. Check in this order.
#1. The audience tab
Open the campaign, go to Audience, and filter by skip reason. This tells you about a specific person straight away.
| Badge | Means | Fix |
|---|---|---|
| Sending | Actively receiving steps | Nothing wrong |
| Pending | Enrolled, next step not due yet | Wait |
| Daily limit | At 2 emails in 24 hours, the next step is skipped | The daily cap |
| In another campaign | Already in a different drip | One campaign per contact |
| Opted out | Unsubscribed or suppressed | Cannot be fixed, and should not be |
| Recent bounce | Bounced in the last 30 days, skipped at enrolment | Check the address is right |
| Completed | Finished all steps | Nothing wrong |
#2. The pre-flight card
At the top of the Audience tab: total contacts, how many will actually receive, how many are skipped and why. Use it to see whether the problem is one person or a pattern.
#3. Email Health
In the Drip Campaign Builder. Shows the last 7 days of skips by reason, click a reason to see the exact addresses. Also where a Sending paused row appears if your account is locked out.
If no campaign is sending, this is why. A lockout shows here with a countdown. See Auto-pause and lockouts.
#4. Analytics → step recipients
For per-step, per-person delivery: Analytics → Step Recipients, which shows delivered, opened, clicked, bounced and unsubscribed for each recipient, and exports to Excel.
#Common causes, fastest first
| Symptom | Usually |
|---|---|
| Nothing sends, any campaign | Email domain not verified, see Verifying your domain, or an account lockout |
| One person gets nothing, everyone else fine | They unsubscribed, hard-bounced, or are in another campaign |
| Some contacts skipped on one step | The daily cap. Something else emailed them that day |
| Campaign stopped mid-way on its own | Auto-paused after two hard bounces |
| Second campaign reached almost nobody | The one-campaign rule, they were already in the first |
| Contact shows No email | The record has a placeholder address from import. See What the importer fixes for you |
#It sent, but they say they never got it
Delivered but unseen is a different problem from not sent. Check the step recipients view, if it says delivered, the email reached their mail provider. From there it is spam filtering or the person not looking.
If that is happening broadly, the usual cause is an incomplete domain setup. Everything in The DNS records exists to prevent exactly this.