Mail acting screwy

I have 2 mail accounts set up. One works fine, but the other gives me this message when I try to send from it (receiving works OK):

The connection to the server “smtp.cox.net” on port 995 timed out.

Select a different outgoing mail server from the list below or click Try Later to leave the message in your Outbox until it can be sent.

If I delete the account from my Mac Mail app and re-add it, it works for a short while, and then does the same thing again.

Can anyone advise me on this?

Thanks

Randy


P.S. Running ML on a late 2011 MBP

By the way, the mail acct is working fine on my PC and on my iPhone 4S

Tried this:

Deleted offending email account
Reset PRAM
Re-added the email account

Same thing happens

Since it works as it should in iOS, this must be an OS-X problem, right?

I am kind of new to mac's, so forgive any ignorance on my part