Email Security.cloud blocking

[Hugo Whittle]

Hello,

For over three years we've had issues sending emails to Email Security.cloud (and formerly Messagelabs / Symantec Cloud) customers when the messages contain references to our domain vtx.uk or vtx.co.uk (we switched from using .co.uk to .uk in an attempt to solve this problem, but it didn't help).

In the past, removing the domain where it appeared in the body of the email was sufficient to allow the message through - a tedious but workable solution.  However, the messages now appear to be blocked even without any mentions of the domain in the body, so I assume it is being picked up in the From: header.  This means that we are unable to send emails to some of our most important customers.

Note that this is not related to the particular mail server which is sending the message (we use Office 365), but only its content.  Messages containing our domain sent from a Gmail account to the same customers are blocked in the same way.

Sometimes the blocking results in a bounce message, always containing the content "553 Message filtered. Refer to the Troubleshooting page at;http://www.symanteccloud.com/troubleshooting for more;information. (#5.7.1) ".  However, in many cases the messages are just silently dropped, so we have no idea that they haven't been received.

I've sent 13 examples of these bounces to [e-mail] since this problem started.  Of course I never know whether that has any effect, and in many cases the problem just goes away without my taking any action, only to return a few months later.  I've have just sent two more examples (at 2020-07-07 16:04 UTC and 2020-07-07 16:07 UTC).

I have a monitor set up to watch the URI DNSBLs provided by SURBL.org, Spamhaus DBL and URIBL.com, and I've never found our domain on any of them.  Additionally, our messages are signed and pass SPF, DKIM and DMARC.

Could you let me know please how I can remove our domains from your blacklist as quickly as possible and why they are being listed in the first place so I can prevent it happening in the future?  This is now having a severely detrimental effect on our ability to do business.

Thanks in advance for your help,
Hugo

[Hugo Whittle]

Just wondering whether anyone from Broadcom could take a look at this.  It seems to be a rather commonly-reported issue.

Thanks,
Hugo

[Sym_Y]

Hi Hugo,

Please excuse the delay.

Can you please message me privately with the email address you used to submit the most recent samples ?

Regards,
Yamma