AOL has changed their email system in a way that will cause some emails not to be delivered: see: http://postmaster-blog.aol.com/2014/04/22/aol-mail-updates-dmarc-policy-to-reject/ SO if you are receiving HT emails at an AOL.COM address, you might want to consider adding another email address to the HT list. Note: You might see this issue with other emails from/to AOL Rich/webmaster