One site, many senders

Set up multiple mailer connections in BooleanSMTP Free, route messages by From address, and see what happens when a connection fails.

BooleanSMTP Free can keep several mailer connections on one WordPress site. For example, a store can send order receipts from orders@example.com through one provider and support replies from support@example.com through another. The From address supplied by the sending plugin determines whether either connection is selected. You can also choose a default for mail without a matching sender and a separate connection to try when a send fails.

Plan your senders

Give each connection its own From Email. In Free, one address belongs to one connection, even when that connection is inactive. BooleanSMTP refuses to save a second connection with the same address; it does not replace the first one. To move an address to another provider, edit its existing connection or change the first connection’s address before creating another.

Connection	From address	Intended use
Store mail, Amazon SES	`orders@example.com`	Order and account messages that explicitly use this From address
Support mail, Custom SMTP	`support@example.com`	Support messages that explicitly use this From address

These are examples. Choose providers that allow the addresses you configure, and verify each sender with the provider where required. A fallback attempt can fail if its provider will not accept the message’s sender.

Add and test each connection

In WordPress, open BooleanSMTP → Mailers and click Add Connection.
Choose a mailer, enter a Connection Name, and set its From Email and From Name under Connection Details. Complete that mailer’s credentials and save the connection.
Add another connection with a different From Email. Confirm both show Active in Mailers; an inactive connection cannot win a sender match or be used as a fallback.
Open Test Email, select each connection in Select Mailer, and send a test to an inbox you can check. Verify the result in that inbox and in Email Logs.

The Test Email screen tests the connection you select directly. It does not exercise automatic fallback, so a successful test of each connection does not prove that your fallback configuration will work for every sender.

Choose the default and fallback

Open BooleanSMTP → Settings → Delivery & Reliability:

In Default Connection, select the active connection that should handle mail without a matching sender. Choose one explicitly if you want a predictable default. System Default (PHP Mail) means no connection is selected in this setting; BooleanSMTP then uses the most recently created active connection as its primary connection. If none is active, it uses PHP mail.
Turn on Fallback Connection and use Send through to select another active connection. The switch alone does not select a backup. Choose a connection other than the one most messages use, so there is an untried route when it fails.
Decide whether to leave Retry on other connections on. It is on by default and can schedule up to two more attempts on active connections the message has not tried, provided the failed message was logged and the queue worker runs.

The fallback is tried immediately after a send failure. Scheduled retries happen later, starting after about one minute, then about five minutes later if another eligible connection exists. See Fallback and retries for the recovery sequence.

What happens in common scenarios

In this table, Store is active with orders@example.com, Support is active with support@example.com, Store is the Default Connection, and Support is the selected Fallback Connection, unless a row says otherwise. Neither example address is configured as the site’s default sender identity. Each result describes the connection BooleanSMTP tries, not a guarantee that the recipient receives the message.

Scenario	First attempt	What happens next
An order plugin explicitly sends from `orders@example.com`.	Store, because its From address matches.	If Store reports a send failure, Support is eligible for the immediate fallback attempt.
A support plugin explicitly sends from `support@example.com`.	Support, because its From address matches, even though Store is the default.	If Support fails, the selected fallback is the same connection, so it is not tried again immediately. A logged failure may be queued for Store if retries are enabled.
A plugin sends from `news@example.com`, which belongs to neither connection.	Store, the selected default.	A send failure can trigger the immediate Support fallback.
A plugin supplies no From address, or WordPress supplies its usual `wordpress@…` sender.	Store, the selected default.	A site default sender address does not turn this into a sender match. The selected default still decides the route.
Support is inactive, and a plugin sends from `support@example.com`.	Store, because there is no active sender match.	The inactive Support connection is not eligible for immediate fallback or queued retries.
No Default Connection is selected, but both example connections are active.	The most recently created active connection, if there is no sender match.	Select a default if you do not want creation order to decide unmatched mail.
No connection is active.	PHP mail, when no other connection was selected.	Provider connections cannot act as sender matches or fallbacks while inactive.
Store reports a send failure, but Fallback Connection is off or has no Send through selection.	Store fails.	There is no immediate fallback. A logged failure may still be scheduled for another untried active connection when Retry on other connections is on.
Store reports success, but the message lands in spam or does not appear in the inbox.	Store’s send is reported successful.	BooleanSMTP does not start fallback based on inbox placement. Check the recipient’s spam folder and the sender domain’s mail authentication.

Check the route on real mail

Send one ordinary message from each WordPress workflow you want to route, such as an order email and a support notification. If that plugin exposes a From setting, use the exact address assigned to the intended connection. In Email Logs, open each message and check the connection and attempts. A successful send means the transport accepted the message; also check the recipient inbox. If a provider rejects a sender during fallback, inspect that attempt and configure an address the backup provider permits.

To test automatic fallback, use an ordinary WordPress-triggered email and inspect its log attempts when the primary send actually fails. A Test Email send bypasses the fallback retry.