Oh! And some footnotes. If this was/is a known system problem, here it is 12+ additional hours later and no solution. Still can't send email. I'm sorry, but that is really bad customer/technical support. I've got important email to send, and I can't. Email is not a "toy", Cox. People rely on it. People pay for it. You are not holding up your end of the bargain.
And webmail is no solution. And the new "myemail" would be laughable if it wasn't so sad. It loads cuss jar slow, and refuses to load at all on older (but still perfectly viable) hardware. And all of my contacts and distribution lists are in *Outlook*, not myemail. And what's up with the ads? You are not Google providing a service for free, I *pay you* for email services. Spare me the ads.
Lastly, FWIW, the denial of service appears to be location-based, not account-based. That's why my wife can't send email either -- the outage is either regional, or our IP address is being blocked or has become frozen. Figure out how to unfreeze it, please. I've got email to send.