Since the reject message asks to reformat the message have you tried that? Leave the numbers off the subject line and do a simple test message and see what happens.
SNMP error 554 is kind of a generic "we don't like it."
Thanks to both of you. We've gotten further here than I have in months with Verizon customer service.
I have "applied" to my IP removed from the blacklist.
And I did try sending just a "test" email, but it bounced back as well.
One interesting thing I've discovered: if I go to the old version of Verizon netmail (vs. the new version, webmail), my email sends. That's the work around I'm using for now.