A working custom-domain identity that receives through your existing inbox and sends through authenticated MailerZ SMTP.
Before you begin
A verified domain and an alias that forwards successfully.
The SMTP host, port, username and generated password shown in your MailerZ dashboard.
Access to the destination inbox so you can confirm verification messages.
Step-by-step
Confirm your destination account
Make sure the mailbox receiving MailerZ forwards is already working in Apple Mail.
Add the custom From address
Open Mail settings, select the destination account and add your custom-domain address to the available email addresses if your version permits it.
Add an SMTP server
Under outgoing server settings, create a MailerZ server entry using the host, secure port, username and generated password from your dashboard.
Disable automatic settings if needed
If Apple replaces the port or authentication method, turn off automatic connection management for this SMTP entry and re-enter the dashboard values.
Select the address when composing
Choose your custom address in the From menu and send a message to an external inbox.
Copy credentials into the correct fields
This diagram demonstrates field placement and sequence. Use the unique values in your MailerZ dashboard; never copy credentials or verification tokens from a public tutorial.
Field-by-field reference
Treat this as a translation layer between MailerZ and the provider interface.
Your verified custom-domain aliasThe identity recipients should see.Host shown in MailerZSends the message through the authenticated MailerZ relay.Secure port shown in MailerZMust match the selected encryption mode.TLS or STARTTLS from dashboardProtects credentials and message submission in transit.Generated SMTP usernameIdentifies the workspace credential—not necessarily the email address.Generated SMTP passwordAuthorizes submission; rotate it if exposed.Verify the setup
The SMTP connection completes over encryption.
The recipient sees your custom address.
A response forwards back into Apple Mail.
Avoid these issues
Menu names differ between macOS releases.
Do not replace your destination account’s incoming server with MailerZ.
If the From address is rewritten, check which outgoing server Apple Mail selected.
Common problems and exact next actions
Authentication failed
Likely cause: The username, password, port or encryption mode does not match the current MailerZ credential.
Next action: Re-copy all four values. If the password may be stale, rotate it and update only this client.
Message sends from the inbox address
Likely cause: The client selected its default identity or default outgoing server.
Next action: Show the From selector, choose the custom-domain identity, and confirm that identity is linked to MailerZ SMTP.
Verification message never arrives
Likely cause: The alias or destination is not forwarding successfully yet.
Next action: Test inbound forwarding first from another provider, then repeat the client’s ownership-verification step.
Provider interface details can change. Check Apple Mail User Guide
Configure one address, then prove the full loop.
Receive a message, reply through SMTP, and confirm the expected From address before moving your whole domain.