New Cox Email - Problem with Blocking

Is anyone having problems with the new Cox email? I use Apple Mail on my Mac, which has always been problematic with Cox, but it now appears that some of my regular email contacts are receiving bounce back messages when they email my cox.net account, saying the email is unavailable. 

In the web interface, I have no spam messages, which makes me wonder if Cox is blocking so much of my email so that people I want to hear from are unable to reach me.

I run a consulting business and need to know that clients and potential clients can reach me. It's probably time to give up on Cox and switch my business account to Gmail. 

Thanks.