Some emails bouncing to known good addresses

[#1]

I am getting failures on some emails to email addresses that I know are valid. I am just replying to emails I just received.

Here is the error:

Reason: SMTP transmission failure has occurred
  Diagnostic code: smtp;554 Service unavailable; Client host [vms173005pub.verizon.net] blocked using Barracuda Reputation

Anyone have any ideas. Sounds like verizon's email servers are being blocked.

[#2]

The IP Address for [vms173005pub.verizon.net] is 206.46.173.5.  According to http://www.barracudacentral.org/reputation,  that IP address is not currently listed as "poor" on the Barracuda Reputation System.  So... I'm looking into it :).  Is your verizon IP static or DHCP? 

[#3]

Also, are you connecting to the internet thru Verizon (when sending) or another provider? 

[#4]

The emails are being sent through Verizon's email servers. I requested to be removed. The only thing I can think of that may have caused this was sending an email with quite a few bad email addresses that were returned. Probably was around 8-10.

Will see if they accept the explanation and leave it out. Some pretty tough rules if only a few bounced emails get you on the list.

thanks

[#5]

The only thing that I would suggest is that you try to send an email from your mail client on the same pc, but instead of using your main Verizon email account, use one of your sub accounts.  This would let you know if the address or the IP has been blacklisted.