Hi decipher:
For the last month, MANY Cox email customers have been having difficulty with some of their email addresses.
This is due to Cox migrating their email system to new servers, etc.
There are currently 2 Forums on the Cox's Forum page, addressing tons of complaints about ongoing email issues, no delivery of emails, can't receive emails, can't send emails, etc.
If you take a minute and read the forums, you will see you are NOT alone.
Also, many of us on the Forums who have posted there, are also in daily contact with cox.help@cox.com.
I suggest you also email Cox Support.
If you call Cox Support, you will undoubtedly speak with a Cox Tier 1 or Tier 2 support person. They will have you change all kinds of settings in Outlook, tell you it could be your anti-virus or firewall, or Microsoft is having difficulty, when in fact, it is none of the above.
Tier 1 and Tier 2 won't tell you it's a problem with their migration to the new email system and that they are working on the issue, and that they know about it. (However, if you write to cox.help@cox.com, those folks will tell you it's an ongoing issue they are aware of and have their engineers working on it).
Most of us have been having the email issues for a month now..............and no fix yet for most of us.
I have 3 cox email addresses, yet only one of them is having the late delivery or no delivery emails to just my one address......the other 2 are working fine.
Here's the link to the current Cox Forum addressing all the email issues going on: (Forums called Random Email Failures)
http://forums.cox.com/forum_home/internet_forum/f/5/t/17963.aspx
This second link was "locked" (on June 8th) by Cox before a resolution had ever been accomplished, hence the second Forum (above) was started. Even though this next link is "locked", you can still refer to it and read through it to see all the email issues so many have been having for a month now. Very good info on this locked forum.
http://forums.cox.com/forum_home/internet_forum/f/5/t/17853.aspx
I suggest you email Cox at that Cox Help email address, and also join in on the current Forum (at that first link), as we are all keeping each other posted on our email situations.