Have done. I've tried all the combinations I can think of. mail.ntlworld.com goes straight to forbidden. virginmedia.com, clicking on email takes me to forbidden. virginmedia.com, sign in, email takes me to forbidden (or sign out, sign in again).
Fortunately mails are still coming in on my phone (IMAP), so I can at least acknowledge them.
I am having the same problem. It is through the Chrome browser. I can access via a different browser, and also via Chrome from a different computer, but even when I reboot the original computer I can no longer access my VirginMedia account via Chrome from my main computer. Interestingly I CAN access a different VirginMedia account I have, just not the main account which I now use as my personal e-mail address.
As with the previous comments, the page I get is a blank white page with "Forbidden" written at the top left. I am assuming this is a 403 error.
Technical Help told me the only way to resolve this is to do a full re-set of my browser, which will lose all of my bookmarks (I have 251, all nicely classified in different folders, so it would be more than a pain to lose them!) and probably all of my stored passwords as well. It would actually be easier for me to ditch my Virgin e-mail and use a different one as my personal account rather than do that.
Superuser 2017/18 Use Kudos to say thanks Mark answer as "helpful" only when the problem is solved Please don't send me private messages unless I ask you to. I do not work for VM. The advice I give is based on my best understanding of VM policy and practice. You rely on it at your own risk.
I posted again because I hadn't noticed there was a thread on this very topic, so when I saw there was I thought it best to post there. For some reason I got notification of your answer here, but not of Shelke's there.