While awaiting the arrival of snowmaggeddon here in the northeast, I had a few clients call me with complaints of no email service. That's always disturbing, especially in cases where I have just recently been visiting… and tinkering. "That Rob, he's always tinkering…"
The sudden loss of email connectivity can create quite a panic. But here's the good news: it's almost always temporary, and it usually has nothing to do with your own computer, your settings, or your own in-home/office wifi or network connection.
When your email goes down, here's a few things to check:
Do I have other Internet features? Does my web browser still connect? If so, you know your connection is OK.
Can I get my email from the web interface? In other words, if you usually use an "email client," i.e. Mail App, Outlook, Inbox, Cloud Magic…, can I get my mail by using Safari, Chrome, Firefox, etc. (If so, this is almost always an indication that POP/IMAP service is down with your provider, and it will be fixed soon.
Is there a problem with my ISP or mail host?