Bounced email help

[#1]

Hi,
Can anyone help me decipher the message below...for the last 3-4 days, when I reply to emails from this person, my emails are bounced. There's no problem when I compose a new email!
Thanks in advance for your words of wisdom,
Stuart
The following message to <XXXXXXXXXXX@supanet.com> was undeliverable.
The reason for the problem:
5.1.0 - Unknown address error 550-"Callback setup failed while verifying <account@username.plus.com>\nCalled:  84.92.1.97\nSent:    initial connection\nResponse: 554-mx.ptn-ipin02.plus.net\n554 Your access to this mail system has been rejected due to the sending MTA's poor reputation. If you believe that this failure is in error, please contact the intended recipient via alternate means.\nThe initial connection, or a HELO or MAIL FROM:<> command was\nrejected. Refusing MAIL FROM:<> does not help fight spam, disregards\nRFC requirements, and stops you from receiving standard bounce\nmessages. This host does not accept mail from domains whose servers\nrefuse bounces.\nYour return address <account@username.plus.com> does not appear to\nbe valid. Sender verify failed.\nSun, 24 Oct 2010 21:53:37 +0100 on host 213.40.66.36"

[#2]

I think it's trying to tell you that the quoted return address account@username.plus.com (which I assume you've disguised) does not exist (i.e. you don't have a mail box or alias called account). So the supanet.com mail server refused to accept the message.
Is that return address different from the one you supply when writing new messages?

[#3]

Hi,
Thanks for the note. No, as far as I can see there is nothing different in the email addresses.
I have also just tried forwarding the email to my work account (nothing to do with plusnet) and then onto the supanet person and my work account gets the same bounced message.
It sounds like either supanet is having some sort of problem OR the bounced message is not accurate and the actual problem is with the message content.
If you have any other ideas, please let me know.
Stuart

[#4]

Quote from: spraxyt

I think it's trying to tell you that the quoted return address account@username.plus.com (which I assume you've disguised) does not exist (i.e. you don't have a mail box or alias called account). So the supanet.com mail server refused to accept the message.

Actually, I think the receiving MTA has a poor SenderBase reputation, and during the receipt of mail it checks that it can send a bounce message to the sender.  This process fails, and the receiving MTA then fails receipt of the message.
The problem is that the Supanet mail server has the poor Senderbase reputation, which is a matter that can only be fixed between Supanet and Cisco/Ironport.
Alternatively, it may be possible for Plusnet to whitelist the Supanet mail servers temporarily, but that's more a question for Bob?
B.

[#5]

I've just today had a stack (about 15) of these messages, pretending to notify delivery failure or return my messages (which of course I've not sent), all with false addresses before the @ then my email after @.  [I receive them because I find it useful to have any message @my address delivered, so I can invent temporary addresses.]  Is this a new form of spam, doubtless with a nasty in the attachment?

[#6]

It's referred to as backscatter and is certainly not a new phenomenon.
Give it a few days, and it will stop.
B.

[#7]

Thanks, Barry, link was instructive.  As far as I can see all the counter-measures it advocates are down to ISP's, except for care in advertising one's email address, which is not the problem here as the addresses involved have invented first parts.  Is there anything else I can or should do - I have been forwarding the messages as attachments to spam@spamtraining.plus.com but maybe that is not helpful?  You say they will stop in a few days, but not much sign of that 12 days later, although numbers reduced somewhat.  Is that because ISP's during this time are dealing with the original spammers, and since the bouncing is as a result of them detecting spam, there's no point in my reporting it?  Are ISP's getting cleverer at not bouncing false emails?
Cheers, Swift