What’s the first step after a domain gets blocked?

When a domain gets blocked, immediate action prevents further damage.

Step 1: Stop sending:

Pause all campaigns on the affected domain immediately

Stop warmup activity

Don't try to send through the block

Document when the block was discovered

Step 2: Identify the block:

What provider or blocklist issued the block?

Check SMTP bounce messages for specific blocklist mentions

Run blocklist checks on domain and IPs

Review Postmaster Tools for provider-specific data

Step 3: Investigate root cause:

What campaigns were running before the block?

Any list quality issues (high bounces, complaints)?

Authentication failures?

Volume spikes or pattern changes?

Step 4: Document findings:

Create timeline of events

Identify specific triggering activity

Determine what remediation is needed

Do not rush to delist:

Delisting without fixing root cause leads to re-listing

Blocklist operators want to see genuine remediation

Understanding the problem comes before requesting removal