We have instructions for both default SMTP port and alternate SMTP port configurations - alternate port is generally used if your ISP blocks the normal port 25 SMTP access (as many do these days!).
Open Mac Mail on Yosemite by clicking the Icon
Go to the Mac 'Mail' menu and click 'Preferences'
Click on the Mac Mail account you wish to edit, you may have multiple accounts so if you do you will need to edit each one separately
Click on the 'Outgoing Mail Server' drop down menu and select 'Edit SMTP Server List...'
Click on the plus (+) button to add another SMTP server
For the description enter 'AuthSMTP'
For the Server Name enter 'mail.authsmtp.com'
Go to the 'Advanced' tab
Untick 'Automatically detect and maintain account settings'
Set the port to '25'
Click on 'Authentication' and select 'MD5 Challenge-Response'
Enter the AuthSMTP Username and Password that has been emailed to you
You have now setup the AuthSMTP outgoing mail server
Please ensure that 'AuthSMTP' is selected in the drop-down menu next to 'Outgoing Mail Server'
Close the window
When prompted click 'Save' to keep the changes
When you first click 'Get Mail' or go to send an email you may need to re-enter your AuthSMTP password
We recommend that you save the password in your keychain
If you would like to use your AuthSMTP service with multiple accounts you just need to click on the account you wish to edit, click on the 'Outgoing Mail Server' drop down menu and then select 'AuthSMTP' from the list of servers.
Are you having a problem sending email or looking for a reliable SMTP server?
AuthSMTP is the outgoing SMTP email service for your e-commerce website, mailing list or email program.
It works on most current computers or devices and solves many of the common problems with sending email such as relaying denied errors or blacklisting issues.
With instant setup, a money back guarantee and very low cost starter accounts you can test and start sending email in minutes with no risk.