Thanks for the reply, but this thread seems to be advice for Virgin users to change their settings to help receive emails that are currently being blocked for spam, it doesn't help our issue of "failed - 421 4.0.0 mx1.tb.ukmail.iss.as9143.net bizsmtp Too many simultaneous sessions".
I have sent you a private message with the email headers.
Virgin have introduced rate limiting on their Mail Exchangers as an anti spam measure.-- However in my opinion the rate limiting is excessive. Looking at some of the threads today Virgin are even rate limiting Gmail and kundserver.de servers - which I believe are used by 1&1 (someone correct me if I'm wrong).
This means that anyone using Gmail, Google Apps for work, Google Apps for Education and anyone who uses a 1&1 hosted email service can expect to see emails to ntlworld.com, blueyonder.co.uk, virgin.net AND virginmedia.com addresses can expect to see their emails delayed and possible bounced if the rate limiting causes the outgoing mail to be queued for too long.
I've already said the Spam content filtering is too excessive. Rather than fix this Virgin have made their anti spam measures even more aggressive, while it may well be having the desired effect of reducing spam. It is having the undesirable effect of impacting legitimate mail flow.
Edit - BTW here's another example of how Virgin's anti spam measures are screwing things up. Reported in May but I only just found this yesterday. Because of the area the paper reports for they'd most likely see failures for virginmedia.com and ntlworld.com domains. But this will also be impacting blueyonder.co.uk and virgin,net email users elsewhere.
I've followed Emma's request by PM, but still no resolution to this problem, Virgin Media are ignoring a widely reported issue and thousands of our customers every week are failing to receive vital information from us. Who can we report this to - Ofcom?