If you have Comcast as your ISP make sure to change your server port from 25 to 2525.
Please note these instructions are provided as a courtesy. We do not directly support, endorse or represent 3rd-party software. Please contact Apple support if your software is not working properly.
1) From the Mail menu, select Preferences.
2) Go to the Accounts tab, and then click the plus sign(+) at the bottom of the Accounts box. In the Add Account window, enter your full name, email address and email password. Click Continue.
3) In the Incoming Mail Server screen, select POP or IMAP from the Account Type list, and complete your information like below and click Continue.
4) In the Outgoing Mail Server screen complete your information like below.