A working custom-domain identity that receives through your existing inbox and sends through authenticated MailerZ SMTP.
Before you begin
A verified sending domain in MailerZ.
A WordPress administrator account.
An SMTP plugin that supports custom SMTP credentials.
A dedicated MailerZ credential for this site, if available.
Step-by-step
Install a reputable SMTP plugin
Choose a maintained plugin that supports a custom SMTP server, encrypted authentication and a built-in test message. Review its data handling before enabling optional logging.
Set the From identity
Use an address on your verified domain, such as website@yourdomain.com. Make the display name recognizable to customers.
Enter MailerZ SMTP details
Copy the host, port, encryption mode, username and generated password from the MailerZ dashboard. Do not guess or use the example text on this page as a credential.
Protect the credential
Prefer your host’s secret or configuration mechanism when the plugin supports it. Restrict WordPress administrator access and never publish the password in a support ticket.
Send and inspect a test
Use the plugin’s test tool, then trigger a real password-reset or form notification and check MailerZ delivery history.
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
Plugin test reports authenticated delivery.
A real WordPress workflow arrives successfully.
From and Reply-To behavior matches your support process.
The message appears in MailerZ delivery history.
Avoid these issues
WordPress plugins can store or log message content; enable logging only when needed.
Bulk newsletters and unsolicited campaigns are outside the intended transactional setup.
Plan limits still apply: Agency supports up to 25 send-as messages per hour and 800 outgoing messages per month; lower plans have smaller limits.
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 WordPress documentation
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.