Email handshake with Verizon mail

[TerribleTed1]

I have been getting reports from verizon/mac users that mail is being rejected by my mail server.  I have many hundreds of folks who use Verizon and Frontier

It appears to be the HLO command which varies from the HELO command.  Here is the detailed reject notice:

From: postmaster@mac.com

Date: May 17, 2016 at 3:26:14 PM EDT

To: {edited for privacy}

Subject: Delivery Notification: Delivery has failed

This report relates to a message you sent with the following header fields:

 Message-id: <C00E70C2-4F53-4D7B-ACF0-D0C7BB2C2F1E@mac.com>

 Date: Tue, 17 May 2016 15:26:14 -0400

 From: Kim Barley <{edited for privacy}>

 To: {edited for privacy}

 Subject: test

Your message cannot be delivered to the following recipients:

 Recipient address: {edited for privacy}

 Reason: Server rejected MAIL FROM address.

 Diagnostic code: smtp;502 5.5.1 Command unrecognized: "HLO st13p15im-asmtp004.me.com"

 Remote system: dns;mail.kwp.org (TCP|17.164.72.58|47606|69.33.212.210|25) (mail.kwp.org ESMTP Merak 4.2.3; Tue, 17 May 2016 14:26:15 -0500)