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