What URL are you using? https://idm.west.cox.net/coxlogin/ui/webmail?
I can log in both Classic and Enhanced. But with enhanced I had to stop then F5.
As for sending email through Gmail, define secure? They allow a 2-step authentication, give you access to IP that have accessed your account and give you a force boot option. They also allow multiple IMAP sessions and use TLS 1.4. So in that way they are very secure. Not to mention their uptime is very high. Where people avoid using Gmail is when there are privacy concerns. Thats because Gmail's computers "read" every email and use it for advertisement customization, anti-spam, and knowing your personal preferences. Most of this is done to predict what you want done with a email before you even know it, but it also means your emails are out there floating in the cloud. A very nice, secure cloud, but a 3rd party cloud none the less.