Still a glitch...
The blacklisting error appears to have been the main error and affected others, but it may not have been the initial problem that prevented me from getting emails from the Cox server . Fixing the blacklist immediately cured the problem on the Armstrong network (address ends in zoominternet.net). I switched to my other server (address ending in cox.net) and got no more emails last night. As described above, I am not confident in the quality of responses from the Cox technical service people. After that trial with Cox.net, I switched to an email address ending in ".org" (that address will be obvious) that uses the Cox server and received a few emails this morning with appropriate time stamps from threads I am subscribed to.
I then switched back to the Cox.net address and have not gotten e-mails for a subscribed thread. I believe that address may be corrupted at the ETO end and regardless of how many times I try to refresh it, it simply pulls up the old, corrupted address (a cookie?) and uses that. @EM, can you look into that possibility?
John