We are an ESP and one of our client (a well known retailer) is hexperiencing ongoing issues delivering to Virgin Media addresses (virginmedia, ntlworld and blueyonder).
Emails are sent to optin users only, unsubscribes are processes immediately and we respect all your guidelines regarding authentication, technical setup etc.
We have tried to contact your postmaster team several times, providing them with all requested information (headers, error message, orginal source code) but we are not hearing back.
Could you please let me know what to do as this issue is impacting our client, and legitimate mail for which your users have subscribed is not getting delivered?
I am sincerely sorry about the issues your client is having when sending mail to our domains. But I'm glad you've posted on here as I know we can help resolve this.
To be honest this type of issue, up until very recently, would have most likely been caused by our default mail spam options being set to reject all spam.
Yours is the first issue we've had since then so I'll be interested to see what's causing the rejections and get this remedied for you.
Please reply to my PM (purple envelope icon, top right of page) with the requested information and I'll get this matter progressed immediately.