Email issues

I am on Shaw here in Canada but it may be for any IP, I could not send emails said off line though my phone and Ipad worked, the Mac, has pop3 as the server, it never got changed. Any way I thought I would delete the account in preferences and reinstall the account, when I try it says account already exists. I tried a new account Imap, Exchange, and I could not get it to add the account, The mac is still running Mavericks.

The account is fine through webmail, and through Ipad and Iphone any ideas?

Thanks in advance