Open Mail.

Click on the Mail menu and select Preferences


Click OK
At this point, Mail will attempt to contact the mail server. If it fails, click the Continue button on the warning message that appears to continue with the set up.
You will then be asked to Import Mailboxes. Click the No button, unless you want to import email from another mail program.

The Welcome dialog box will appear. Click the No button.

Click on the Mail menu and select Preferences
Click the Server Settings button under Outgoing Mail Server (SMTP)

Change the server port number from 25 to 587
Change Authentication to Password
Enter your email address
Enter your password

Click OK and you will have completed the setup.