Valid email returned to me as spam

[#1]

I forwarded a newsletter from a reputable software company to my husband at his Plusnet address but it's been sent back to me via my email provider (I couldn't get it to go via my Plusnet address so I used a different one) saying the Plusnet mail server has rejected it as spam. Is there any way I can notify someone that this is NOT spam? I'm rather concerned that this has happened as I would never send out spam and don't want to be blacklisted.

[#2]

If you try sending a test email to your husband via the same route does that bounce back? Just wondering of the problem is that any message sent via your email provider's server is rejected.

[#3]

Haven't had anything like that happen before and trying this morning I haven't had a test email, as you sugget, sent back. It's Apple, so I'd think it's something to do with the message rather than the mailserver.
When I originally tried to send it via my Plusnet address I kept getting messages popping up to say the server couldn't send it and to try a different one so assumed there was some glitch or other and sent it by the other address. It went through fine from my .mac.com address to his.

[#4]

Yes, it looks like the problem is message-related rather than the sending mail server's reputation.
However as far as I'm aware poor Cloudmark Sender Intelligence reputation is the only check that results in a bounce. If that passes the message could be deleted if rated as "obvious spam" (if that is turned on in Manage My Mail Spam settings), but that should not result in a bounce.
I think you might need to raise a ticket on this problem and attach the offending newsletter (enclosed in a zip file).

[#5]

Quote from: Mad

I couldn't get it to go via my Plusnet address so I used a different one

What happened when you tried and what was did it say in the content of the message you sent from the non-Plusnet address that was returned to you?
Chances are there was a spam fingerprint signature in it. It's be a long string of characters/numbers. If you raise a support ticket containing this information then we can look into what's triggering the spam filter and get it sorted for you.

[#6]

When I tried to send via my Plusnet address it was the standard drop down message that Apple's Mail program gives if a server is unavailable to the sender. Nothing different from usual but I did try to send it a few times. Before I gave up I looked on this forum to see if anyone else was having problems sending emails, which they weren't.
The message I got back after sending from my .mac.com address was as follows (with addresses disguised):
This report relates to a message you sent with the following header fields:
Message-id: <F9F4E859-9C31-4B8C-9DEA-D06D07662D52@mac.com>
Date: Tue, 26 Mar 2013 14:31:56 +0000
From: XXX <xxx@mac.com>
To: YYY <yyy@zzz.plus.com>
Subject: Fwd: QuarkXPress Newsletter - March 2013
Your message cannot be delivered to the following recipients:
Recipient address: yyy@zzz.plus.com
Reason: SMTP transmission failure has occurred
Diagnostic code: smtp;552 Spam Message Rejected
Remote system: dns;mx.avasin.plus.net (TCP|17.172.204.236|62929|212.159.8.200|25) (avasin07.plus.net Plusnet Cloudmark Gateway ESMTP server ready)
Original-envelope-id: 0MK900LD4V1AHJ20@st11p01mm-asmtp001.mac.com
Reporting-MTA: dns;st11p01mm-asmtp001.mac.com (tcp-daemon)
Arrival-date: Tue, 26 Mar 2013 14:32:00 +0000 (GMT)
Original-recipient: rfc822;yyy@zzz.plus.com
Final-recipient: rfc822;yyy@zzz.plus.com
Action: failed
Status: 5.0.0 (SMTP transmission failure has occurred)
Remote-MTA: dns;mx.avasin.plus.net (TCP|17.172.204.236|62929|212.159.8.200|25)
(avasin07.plus.net Plusnet Cloudmark Gateway ESMTP server ready)
Diagnostic-code: smtp;552 Spam Message Rejected
From: XXX <xxx@mac.com>
Subject: Fwd: QuarkXPress Newsletter - March 2013
Date: 26 March 2013 14:31:56 GMT
To: YYY <yyy@zzz.plus.com>

Begin forwarded message:
From: "QuarkXPress Newsletter" <newsletters@quark.com>
Subject: QuarkXPress Newsletter - March 2013
Date: 26 March 2013 09:36:22 GMT
To: xxx@zzz.plus.com
Reply-To: newsletters@quark.com

The newsletter itself is here, exactly as it appears in email: http://tinyurl.com/d6cdtdy
I've checked my email spam settings and the way I have it set it should only bounce back to senders of mail "from a mailserver with a bad Cloudmark Sender Intelligence reputation". Seems very odd what's happened then as the original newsletter email was sent to my Plusnet address. Just to be safe next time, I've added my .mac.com email address to the whitelist, so this shouldn't happen again!

[#7]

I've checked the content of that message and nothing in it is falling foul of Cloudmark's content filters. It may have been when you originally tried forwarding it though.

[#8]

Thanks for checking.