Connect SMTP2GO
One of the easiest to set up, with a free 1,000 emails/month forever.
SMTP2GO is one of the simplest providers to get started with, and its free tier (1,000 emails/month) never expires.
SMTP settings at a glance
| Setting | Value |
|---|---|
| Server | mail.smtp2go.com |
| Ports | 2525 (recommended) · 587 · 8025 · 25 · 465 (SSL) · 8465 / 443 (SSL) |
| Username | The SMTP user you create (Step 2) |
| Password | That SMTP user's password |
SMTP2GO recommends port 2525 — it's open on most networks.
Step 1 — Verify your sender domain
- In SMTP2GO: Sending → Verified Senders → Sender domains → Add sender domain.
- Add the three CNAME records (SPF, DKIM, tracking) at your DNS host, then verify.
Verifying your domain also removes the free-account limit of 25 emails/hour.
Step 2 — Create an SMTP user
- Sending → SMTP Users → Add SMTP user.
- Set a username and password, then save.
Step 3 — Paste into Mailbo
- Settings → SMTP & sending → click the SMTP2GO tile.
- Sender: From email (on your verified domain) + From name.
- Credentials: Username and Password = the SMTP user from Step 2.
- Save, then Send test email.
Troubleshooting
| Problem | Fix |
|---|---|
| Connection blocked | Use port 2525 (most reliable); your network may block 25/587. |
| Stuck at 25/hour | Verify your sender domain (Step 1) to lift the free-account hourly cap. |
| Domain won't verify | SMTP2GO uses CNAME records (not an SPF include:) — add them exactly as shown. |
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Last updated 6/15/2026← More in Sending & Deliverability