This is the mail system at host mail.zapf.in. I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below. For further assistance, please send mail to postmaster. If you do so, please include this problem report. You can delete your own text from the attached returned message. The mail system <bobappleby(a)comcast.net&gt;: host mx1a1.comcast.net[96.103.145.163] refused to talk to me: 554 resimta-a2p-650767.sys.comcast.net resimta-a2p-650767.sys.comcast.net 116.202.37.52 found on one or more DNSBLs, see https://postmaster.comcast.net/smtp-error-codes.php#BL000100