In the absence of a reply from the OP, I thought I might give some further input on the behaviour of this problem. I am getting this message when trying to access an article in the forum that appears to relate directly to an issue I'm having in the MPN portal. However, when I click on the link to the article, I get the "Access denied" error, as outlined, above. The URL I am clicking on is:
I realise this is a slightly old post but the problem is still there, obviously.