📤 Setting Up Sending With SMTP

ResultsAiX Mailer writes, schedules and tracks your emails, and a sending service carries them to the inbox. You connect that service once on the Sending screen, and from then on every broadcast, automation email and test goes out through it.

You can add as many connections as you like: any provider, and several accounts with the same provider. The Mailer picks one for each email by priority, or shares the work between them when you switch on rotation.

Where to find it:

In the ResultsAiX Mailer menu, open Delivery, then Sending. The screen has two cards: Sending Providers at the top, with the + Add Sender button, and Send Rotation & Warmup underneath it.

The twelve connection types:

• WordPress wp_mail (default): hands the email to whatever mail setup your WordPress site already has.
• Bring-your-own SMTP: any SMTP server, using its host, port, username, password and encryption.
• Amazon SES
• SendGrid
• Mailgun
• Postmark
• Resend
• SparkPost
• Mailjet
• Brevo (Sendinblue)
• ElasticEmail
• SMTP2GO

The ten named services talk to the provider's own API, which is quicker than SMTP for big sends. Each one has its own article, for example see Connect Amazon SES or Connect Your Own SMTP Server. If you have not chosen yet, see Which Sending Service Should I Pick?

Adding a connection, step by step:

1. Open Delivery, then Sending, and click + Add Sender. The Add Sender form opens.
2. Type a Display name you will recognise later, such as SMTP2GO or Amazon SES (main). Only you see this name.
3. Choose your service in the Provider dropdown. It starts on SendGrid, so change it if you use something else.
4. The form changes as you choose. You see a short note about that provider, a "Set up ..., step by step" checklist, and the boxes that provider needs.
5. Fill in the provider boxes: an API key, a token, or host and login details.
6. Fill in the Routing boxes, explained below.
7. Click Save Sender. You are taken back to the Sending screen and the new connection is in the table.
8. Click Test on its row to prove it works before any subscriber sees an email.

The "Set up ..., step by step" checklist has an Open link next to the steps that happen on the provider's own website, and a "Read the full guide" link that opens the matching guide inside the plugin's Training screen.

The Routing settings:

Every connection has the same Routing boxes under its provider boxes.

• From name: the name on this connection's test emails, for example Anna at Leafwise.
• From email: the address on this connection's test emails. It also tells the authentication badge in Send Rotation & Warmup which domain to check, so use an address on the domain you send from.
• Reply-To: where replies to this connection's test email go.
• Daily limit (0 = unlimited): the most emails this connection may send in one day. A good value is your plan's daily allowance. When it is reached, the next connection takes over, and if none has room left, the rest of the queue waits and goes out when capacity returns.
• Priority (lower = preferred): starts at 100. In Priority + failover mode the lowest number sends first. Give your main service 10 and a backup 20.
• Active: ticked for a new connection. Untick it to park a connection without deleting it. An inactive connection never sends.

Your broadcasts and automation emails normally go out with the From of the email itself, which usually comes from a sender profile (see Sender Profiles). The connection's own From is used for its test, for the badge, and when you choose "Each connection's own From" in Send Rotation & Warmup.

Testing a connection:

Each row in the providers table ends with Edit, Test and Remove.

1. Click Test on the row.
2. The Mailer sends a short email with the subject "[ResultsAiX Mailer] Test send via" followed by the connection's name, through that connection only. It goes to your site's administration email address (the one in WordPress Settings, General).
3. A green box at the top says "Test sent via" and the connection name. Check that inbox to confirm it arrived, and check it landed in the inbox rather than spam.
4. The Last test column on the row now shows OK and how long ago.

Reading the providers table:

• Name, Provider and Active: what you set on the form.
• Priority: the order used in Priority + failover mode.
• Sent today: emails this connection has sent today. It goes back to 0 once a day.
• Daily limit: the limit you set, or the infinity sign for no limit.
• Last test: OK or Failed, with the time. A failed test shows the provider's own words under "Why it failed:".

How the Mailer picks a connection for each email:

1. In the default mode, Priority + failover, the active connection with the lowest priority number that still has room today sends the email.
2. If that connection reports an error, the next one in line tries straight away. The email is not lost.
3. If every connection reports an error, the queue tries that email again twice more, a few minutes apart, before marking it failed.
4. If every real connection has used its Daily limit or its warmup cap, the email simply waits in the queue and is tried again every 10 minutes until capacity returns.
5. WordPress wp_mail always goes last, whatever its priority number, and it never takes over mail that is waiting for capacity.
6. A broadcast can pick one connection in its Send via box. That one goes first and the others stay behind it as backup.

To spread mail across several connections instead, see SMTP Rotation: Spread Sends Across Many Connections.

Bounce and complaint webhook:

As soon as you have at least one API connection, a box called Bounce & complaint webhook appears under the table. It has one URL per provider you use, each with a Copy URL button.

1. Click Copy URL next to the provider.
2. In that provider's dashboard, open its webhook or event notification settings and paste the URL.
3. Switch on the bounce, spam complaint and unsubscribe events.

From then on the provider tells the Mailer about problems with an address. Hard bounces, complaints and unsubscribes are added to your suppression list automatically, and a soft bounce (a full mailbox, say) is logged and only suppressed if it keeps happening. The secret in the URL keeps strangers from sending fake events, so keep the URL private. See The Suppression List and Hard And Soft Bounces.

Bring-your-own SMTP and WordPress wp_mail have no webhook box, because plain SMTP has no way to send these events back.

Editing or removing a connection:

• Edit opens the same form, now titled Edit Sender. Change what you need and click Save Sender.
• If you change the Provider of an existing connection, the old provider's saved keys are cleared when you save, so nothing stale is left behind.
• Remove asks you to confirm first. Nothing already sent is affected. If it is your only active connection, add another before you send again.
• If you remove the WordPress wp_mail entry, it stays removed after plugin updates.

A real example:

Leafwise Gardening (yoursite.com) sends its newsletter as Anna Hale from anna@yoursite.com. Anna's Sending screen has four connections:

• Amazon SES (main), priority 10, Daily limit 50,000.
• SMTP2GO, priority 20, Daily limit 5,000, still warming up.
• Postmark (broadcast stream), priority 30, Daily limit 10,000.
• WordPress wp_mail, priority 100, kept only as the last resort.

Each connection has From email anna@yoursite.com and Reply-To hello@yoursite.com, and each passed its test. Today SES has sent 412 emails, SMTP2GO 188 and Postmark 96, because Anna shares the load with Weighted shares of 60, 20 and 20. All three API services have their webhook URL pasted in, so a bounce at any of them reaches her suppression list within seconds.

Tips:

• Test every new connection before it carries a broadcast, and test again after you change a key.
• Put your plan's daily allowance in Daily limit. The Mailer then paces itself instead of being cut off halfway through a send.
• Set up SPF, DKIM and DMARC for your domain before your first real send. See Deliverability: SPF, DKIM And DMARC.
• Paste the webhook URL into each provider on the same day you connect it.
• Keep a second connection with a higher priority number as automatic backup.
• On a brand new account, switch on warmup for the first weeks. See Warmup: Drip A Big Send Through A Cold Server.

If something does not look right:

• If Last test shows Failed, read the "Why it failed:" line under it. Those are the provider's own words, and they usually name the exact box to fix.
• If the message mentions an unverified sender, verify the From email or its whole domain in the provider's own dashboard, then click Test again.
• If the message mentions blocked or unexecuted requests, your web server is not allowed to reach the provider. Check wp-config.php for WP_HTTP_BLOCK_EXTERNAL, or ask your host to allow outbound HTTPS.
• If emails sit in the queue, compare Sent today with Daily limit on each row, and check the warmup caps in Send Rotation & Warmup. Raise a limit or add another connection.
• If an email went out through a different connection than you expected, check Active, Priority, the rotation mode, and the broadcast's Send via box.