Click File and select Account Setting

The Account Settings window will open. Click on the New icon

In the Add New E-mail Account window, select the Microsoft Exchange, POP3, IMAP, or HTTP option and then click the Next button.

In the Auto Account Setup window, place a checkmark in the box next to the option: Manually configure server settings or additional server types. Click on the Next button.

In the Choose E-mail Service window, select the first option, Internet E-mail. Click the Next button.

Enter your name as you would like it appear when sending messages in the Your Name field.

Enter your e-mail address in the E-mail Address field.

Press the down arrow for the Account Type and select IMAP

Type (Replace yourbusinessdomainname with your domain name) for the Incoming mail server (IMAP)

And then type (Replace yourbusinessdomainname with your domain name) for the Outgoing mail server (SMTP) 

Type your User Name (Your email address) and Password (same as used to login to the web application)

Put a checkmark in the Remember Password box.

Click the More Settings button

Click the Outgoing Server tab

Check the box for My server requires authentication

Click on the circle next to Use same settings as my incoming mail server.

Click the Advanced tab

Verify that the incoming port is 143 and the outgoing port is 5125 (*if you have trouble sending email, please use 25)

Click the OK button, then the Next button and then Finish