Email rejected from me to another cox.net customer
I tried to forward an email today to another Cox user and it was rejected:
550 <firstname.lastname@example.org> message rejected. Refer to Error Codes section
at https://www.cox.com/residential/support/email-error-codes.html for more information. AUP#CXSNDR
NOTE: The original email I got was a newsletter which I receive regularly all the time. This one was marked as --SPAM-- ... in the subject line.
However, just to verify I sent a simple text message to person again, and it went through fine! What is the explanation for this behavior?