When you set up a new PowerMTA server, your IPs are "cold." Gmail and Outlook do not trust them yet. If you send 50,000 emails on Day 1, you will be blocked instantly. You must follow a strict Warmup Schedule.
The Golden Rules of Warmup
- Start Low: Never exceed 50 emails per IP/hour on Day 1.
- Target High Engagement: Send to your best openers first. High open rates tell Google your IP is safe.
- Monitor Bounces: If bounces exceed 3%, pause immediately.
30-Day Warmup Schedule (Per IP)
| Day | Max Volume (Daily) | Hourly Limit |
|---|---|---|
| Day 1 | 50 | 5 |
| Day 2 | 100 | 10 |
| Day 3 | 200 | 20 |
| Day 4 | 400 | 40 |
| Day 5 | 800 | 80 |
| Day 7 | 2,000 | 200 |
| Day 14 | 20,000 | 2,000 |
| Day 30 | Unlimited | Unlimited |
Automating Warmup in MailWizz
You don't need to do this manually. In MailWizz, go to Delivery Servers > Update > Limits. Set "Hourly Quota" to match the schedule above, and increase it daily.