To simplify the use of your SMTP Auth Relay, we recommend creating a separate account in your Mac Outlook email client. This separate account has both an IMAP and SMTP server.  

If you are a user of the MailRoute Managed Email Membership Service (MEMS) (such as a member of a professional organization or alumni group) and using only the MEMS email forwarding service, the IMAP account will not store any of your email - it will be forwarded appropriately.

Users of the MailRoute Hosted Email Service have full IMAP mailbox and storage capabilities.

TL;DR (Too Long, Didn't Read)

Gather the info from our Control Panel by clicking the SMTP Auth Relay tab on the left menu.  You'll have to click the eye icon to view your passwords.  If you don't have a local password set up, you'll be asked to create one.  The Inbound (IMAP) and Outbound (SMTP) servers may have different logins and will have different passwords.   Go into your Outlook app, add a new account using those settings.

When you send email, click the From address to choose your new account for sending email.  It'll pass SPF, DKIM, DMARC checks.  Congratulations!

Long Version

Gather the info you need to configure your email client

To configure your email client to use the MailRoute SMTP Auth Relay service for outbound email relay, you will need to gather some info from the MailRoute Control Panel and then configure your email client. 

1. Login to admin.mailroute.net and click the My Settings link at the top of the page.
   
   
2. Click the SMTP Auth Relay tab in the Settings menu on the left side of the page. 
   
   
   
   
3. Gather your info!  You can click the copy icon  to copy the values of any field.
   
   There are separate Inbound (IMAP) Server and Outbound (SMTP) Server configurations.  You'll need both:
   
   
   Inbound (IMAP) Server Password:  Click the eye icon to display your password .  If you haven't set a local MailRoute password yet, you will be prompted to do so.   Your Inbound (IMAP) Server password may be the same as your Control Panel login password.  You'll be shown this, if this is the case.  
   
            
   
   Outbound (SMTP) Server Password:  Click the eye icon to display your password. Accept the Terms of Service:
   
            
   
   By the way, you can generate a new password for your Outbound (SMTP) Server at any time.

Configure your email client

1. Open the Outlook email client on your Macintosh.
   
   
2. Choose Settings from the Outlook menu in your menu bar.  We're going to add a new mail account to your email client.  
3. Choose Accounts from the icons at the top, and then press the + icon at the bottom left of the window to add a new account:
4. Choose Add Email Account
   
5. Enter your email account in the Email Address field, and then click Continue:
6. In the Choose Provider dialog, select IMAP:
7. Now we're finally going to get to set all the final settings for your account!  
   
   In the Add Account window, you can enter your Email Address, your IMAP Username, IMAP Password, IMAP Incoming Server, SMTP Auth Username, SMTP Auth passwword.  Chose StartTLS for both IMAP and SMTP servers, with the ports you saved from the MailRoute Control Panel:
   
   
   
   Then click Add Account.  You'll see a window showing that it was successful:
   
   
8. Now you can close your Settings/Accounts window and use your account!

Using your new account to send email

When you compose a new email, you'll have a menu where the From address is displayed.  Click it and choose your new account from the popup menu: