552 error: message rejected due to spam or virus

[#1]

In a last couple of days I’m unable to send any emails from my account, I still can receive emails without any problems. The error I’m getting is:
The following recipient(s) cannot be reached:

      'xxxx@xxxxx.com' on 10/01/2016 16:51
            552 4GqY1s00B33RQ0H01GqZNW message rejected due to spam or virus. If you believe this is in error please login to your portal or contact your ISP support team.
I’m using Outlook with my own email address (two different addresses and it fails for both), for outgoing settings I’m using Plusnet SMTP server. The messages bounces back almost immediately, without much delay. The same email on my phone over 3G (using different SMTP settings) works without any problems. So, it doesn’t look like my email address was hijacked and used for spam and is blacklisted, it looks more on Plusnet side.
Has anyone come across this, any ideas how to sort it out?
Thanks.

[#2]

Hi Sergei,
A warm welcome to the forums.
To be clear here, is this a NEW email you are sending to this addressee or is it a REPLY to an email from them you are trying to send?
If it is a reply email which is failing, go look in the email you are replying to.  It could well be the email you are replying to (which will be embedded in your reply) has reference to content which is falling foul of the anti-spam filters.  See http://community.plus.net/forum/index.php/topic,147485.msg1298110.html#msg1298110
Note that PlusNet's anti-spam services are fairly tough, so as to protect the reputation of their relay servers.
Kevin

[#3]

Also been repeatedly having this problem when sending new emails "552 d0qj1v00F3beeK3010qlXl message rejected due to spam or virus". In addition having problems sending emails to my wife who uses the same email URL address @xxxxx.org.uk. Have spam filters turned off at every option.

[#4]

There is most likely a URL in the email text which it being caught by the outbound spam filters ... which IIRC you cannot switch off. They being on protects PlusNET's email server reputation for the benefit of all users.

[#5]

I had this a couple of months ago, when a certain website was mentioned in body of the email sent to 15 recipients.

It meant I almost couldn't use my email at all as all email addresses that were associated with it were classed as spam too.

The web address had been flagged for some reason. Bob Pullen sorted it for me. Strange thing was tho' the only other person to be affected was my OH, none of the other 13 people who used a different ISP and received the email were affected.

[#6]

@mickphythian Could you send me the full bounce message including the body of the content and we'll take a look at that, I'd advise to send that via private message.