Layer Seven Hosting

Check:

1. Your password

2. the username would be email@domain.com

3. smtp and pop3 = mail.domain.com  or the  IP assigned to you in your setup email

4. make sure SSL / Secured Socket Layer option is not selected

5. make sure ‘my server requires authentication’ is CHECKED.

Then confirm that the email is created in cPanel. 

Having checked the above then : 

Login to webmail, check if you can receive and send emails from there. If yes, and your email was working right before, then the problem is either with your ISP or your client is not properly setup. Please double check the first group of solutions to make sure the client is properly setup.