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
Choose manual account setup
In your Outlook version, add an account and choose advanced or manual configuration. Interface labels vary between New Outlook, classic Outlook, macOS and mobile.
Enter your address and outgoing server
Use the custom-domain alias as the email address. Enter the MailerZ SMTP host and port from the dashboard and require authentication.
Use the generated credential
Paste the exact MailerZ SMTP username and password. Select the encrypted connection method shown in the dashboard.
Keep incoming mail at its destination
MailerZ forwarding delivers into your existing inbox. Do not invent IMAP or POP settings for MailerZ; use the incoming settings of the mailbox where mail is actually stored.
Send from the new identity
Start a message, show the From field, select the custom address, and send to an unrelated mailbox for a clean test.
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
Outlook accepts the outgoing server credentials.
The recipient sees the custom-domain From address.
Replies reach the destination configured in MailerZ.
Avoid these issues
Outlook variants expose different account flows; use manual/advanced setup when automatic discovery chooses the wrong server.
MailerZ is not an IMAP mailbox. Your destination provider remains the message store.
An organization-managed Microsoft account may restrict adding external send identities.
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 Microsoft Support
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.