Always pay attention to the url of the login page, as ‘fake’ login pages are more and more common. The official Cox Webmail login page is found at https://webmail.cox.net/, and the page should look like the screenshot above. Please note, that the url will then redirect to an url beginning with https://idm.west.cox.net/coxlogin/ui/webmail or https://idm.east.cox.net/coxlogin/ui/webmail.
Cox Webmail login