Connect any SMTP/IMAP mailbox
Connect a mailbox on cPanel, Hostinger, OVH, IONOS, or any other mail server using SMTP and IMAP credentials.
EmailWarmer works with any mail server that speaks SMTP and IMAP — cPanel hosts, Hostinger, OVH, IONOS, self-hosted servers, anything. If your provider isn't Google Workspace, Microsoft 365, or Zoho, this is your guide.
Find your server settings
Your hosting provider publishes SMTP and IMAP settings, usually in one of these places:
- cPanel: Email Accounts → Connect Devices (or "Configure Mail Client") shows exact hostnames, ports, and your username.
- Hosting dashboard: look for "Email configuration", "Mail client setup", or "Manual settings" (Hostinger, OVH, IONOS all have such a page).
- Provider docs: search "your provider SMTP IMAP settings".
Typical hostnames look like mail.yourdomain.com, smtp.yourprovider.com, or a server name like server123.yourhost.com. SMTP and IMAP often share a hostname, but not always — copy both exactly as shown.
Ports and encryption
| Protocol | Port | Encryption | When to use |
|---|---|---|---|
| SMTP | 587 | STARTTLS | The default — use this unless your host says otherwise |
| SMTP | 465 | SSL/TLS (implicit) | If your host only offers SSL SMTP |
| IMAP | 993 | SSL/TLS | The standard for IMAP — almost universal |
The onboarding form defaults to 587 and 993, which is correct for the large majority of servers.
Port and encryption mode travel together. Port 587 expects STARTTLS (the connection starts plain, then upgrades); port 465 expects SSL from the first byte. Entering port 465 where 587 is expected — or vice versa — produces timeouts or abrupt connection errors rather than a clean "wrong password" message, which makes it easy to misdiagnose.
Connect the mailbox
- In the Add mailbox flow, choose SMTP/IMAP.
- Enter your email address and a sender name — the From name on warmup mail (blank = derived from the address).
- Enter SMTP host, port, username, and password, then the IMAP host and port. The use same credentials toggle copies your SMTP login to IMAP, which is right for most servers.
- Run the connection test.
What the connection test does
Before anything is saved, EmailWarmer makes a real SMTP connection and verifies authentication, and performs an actual IMAP login. Both must pass. This means a green result isn't a guess — your server accepted the credentials on both protocols. If either side fails, you'll see the specific error and can fix it immediately.
Common failures
Authentication failed (535 or similar)
- Wrong username form. Most servers want the full email address (
[email protected]) as the username; a few older setups want just the local part (you). Check your provider's mail client settings page for which. - Wrong password, or the account requires an app-specific password.
Connection timed out or dropped
- Wrong TLS mode for the port — see the callout above. Try 587 if you were on 465, or vice versa.
- Firewall blocking the port. Some hosts firewall SMTP ports by default or restrict connections by IP; check your hosting control panel or ask support whether outbound-facing SMTP/IMAP access is open.
- Wrong hostname — a typo, or using the webmail URL instead of the mail server hostname.
SMTP passes but IMAP fails
IMAP may be disabled for the account, or the IMAP hostname differs from the SMTP one. IMAP is required: it's how your mailbox reads and replies to warmup mail — see how warmup works.
Before starting warmup on a custom domain, run the SPF/DKIM/DMARC checker. Self-hosted and cPanel domains are the most likely to have missing DNS records, and warmup works far better on a correct foundation.
Next steps
Continue with the quickstart to configure and start warmup.