Select the "Mail" tab in the Internet Accounts window and click "Add."
Enter you full name and click Next.
Enter your e-mail address and click Next.
On the E-mail Server Names window, enter your information as follows
My incoming mail server is a
Incoming mail (POP3, IMAP or HTTP) server
mail.yourdomain.com (e.g. :--mail.smartweb.in)
Outgoing mail (SMTP) server
mail.yourdomain.com (e.g. :-- mail.smartweb.in)
Enter your e-mail address for your account name and enter your password. Click Next.
Select the mail account you just created and click "Properties."
In the Properties window, select the Servers tab.
Select the "Advanced" tab and change the "Outgoing mail (SMTP)" server port number to 80. Click OK.
Then Click on Apply and OK