Certain email blocked.

Can you explain? Did you block their email? Or did they block yours? 

If you blocked it, do you remember how? Was it through the webmail.cox.net? Or through a email program like Outlook?

You may want to check that the domain itself is not blocked through our Webmail site as well if it is listed it would cover anything from the specific address as well as other accounts from the domain. If neither shows its not likely the account is blocked but may be getting picked up as spam or it is having issues sending out those messages.
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