This guide shows how to configure the Mailster WordPress newsletter plugin to send through Postfaro.
Good news first: Mailster’s SMTP delivery method applies to Mailster’s own emails only. Your other WordPress email (WooCommerce, password resets, forms) is not affected and keeps using whatever it used before.
Mailster’s documentation confirms the SMTP delivery method but does not publish every field label. The labels below are the ones commonly shown in recent versions; if yours differ, look for the equivalent setting. [verify UI path]
Before you start
- Your Postfaro setup is Ready in the panel.
- You have created a sender address for newsletters (for example
[email protected]) and copied its SMTP username and password. - You are a WordPress administrator.
Step 1 — Set the sender
- Go to Newsletter → Settings → General. [verify UI path]
- Set:
- From Name: your newsletter name, e.g. “Acme Newsletter”;
- From Address: your Postfaro sender address, exactly — e.g.
[email protected]; - Reply-to Address: a mailbox you read, or the sender address itself (Postfaro forwards replies to the mailbox you set in the panel).
- Save.
Every Mailster campaign and autoresponder that uses a different From address will be rejected by Postfaro — create a separate sender address in the Postfaro panel if you need one.
Step 2 — Choose SMTP delivery
- Go to Newsletter → Settings → Delivery. [verify UI path]
- Choose SMTP as the delivery method.
- Fill in:
| Mailster field | Value |
|---|---|
| SMTP Host : Port | smtp.postfaro.com : 587 |
| Secure connection | TLS (STARTTLS) — or port 465 with SSL |
| SMTPAuth | On (authentication type LOGIN or PLAIN) |
| Username | Your Postfaro SMTP username (starts with pf_) |
| Password | Your Postfaro SMTP password |
- Save, then use Mailster’s send test option on the same page to send a test email to yourself.
Step 3 — Bounce handling
Postfaro processes bounces and complaints on its own servers and blocks those addresses automatically. You do not need Mailster’s mailbox-based bounce handling for Postfaro sends. Leave it switched off [verify UI path: Newsletter → Settings → Bounce], or, if Mailster asks for a bounce address, enter your Postfaro sender address.
Step 4 — Sending limits: who throttles?
Mailster has its own send limits (how many emails per batch and per period). With Postfaro you have two good options:
| Option | Setting | Effect |
|---|---|---|
| A. Let Postfaro queue (simplest) | Leave Mailster’s limits generous | Mailster hands over the whole campaign quickly. Postfaro spreads it over the following days if it exceeds your daily limit, and emails you a “Batch queued” summary. You can cancel the queue in the Postfaro panel. |
| B. Let Mailster throttle | Set Mailster’s limit to your current daily limit (5,000 per 24 hours — or lower during warm-up) | The waiting happens inside Mailster, so you can pause or edit the campaign in Mailster. Nothing waits in Postfaro’s queue. |
Do not set Mailster’s limit above 5,000 per 24 hours and expect it to be faster — Postfaro’s daily cap still applies.
Mailster sends via WordPress cron. For dependable sending, set up a real server cron job as described in Mailster’s documentation.
Step 5 — Keep your list clean
Mailster adds its own unsubscribe link — keep it in your template footer. Postfaro additionally adds a one-click unsubscribe header and lists bounced, complained and unsubscribed addresses in the panel under Cancelled addresses, with the reason. Postfaro does not write back into Mailster.
After each campaign (or monthly), export Cancelled addresses from the Postfaro panel and mark those subscribers as Unsubscribed or Hardbounced in Mailster (for example by import with status update). [verify UI path]
Troubleshooting
| Problem | What to check |
|---|---|
| “SMTP Error: Could not connect to SMTP host” | Host, port and secure setting (587 + TLS, or 465 + SSL). Some web hosts block outgoing ports 587/465 — ask your host to allow them. |
| “Sender does not match” rejection | The From Address in Mailster must be exactly your Postfaro sender address. |
| Authentication failed | Copy username and password again from the Postfaro panel, or create a new password for the sender address. |
| Campaign seems slow | Check Mailster’s send limits and cron, and the Queue page in the Postfaro panel (daily cap or warm-up). |