I have a MacBook Pro and have been using Apple's Mail App for the better part of 4 years now with no issues (single account). Bought a MacBook Air for my wife recently, running OSX 10.8.3. She uses the Mail App with two email accounts. One for personal use and one for business use. She is having problems sending emails (both email accounts are with Cox Communications - cox.net accounts). She had some funky SMTP settings, which I thought were the culprit, changed server name to: smtp.cox.net for her outgoing email. This seemed to be the fix as she did not have a problem for about 3 weeks. Sadly the problem has returned. Nothing has changed from the settings update last made. Settings are as follows: Use default ports (25, 465, 587) selected Using SSL with password authentication Server name: smtp.cox.net TLS Certificate: None I would appreciate some help. Thanks.