This probably needs someone from the PPRuNe engine room to help as it does seem odd.
But one of the reasons I have never taken up the PPRuNe mail system bigtime is just because I could not view the e-mails directly on-line when I'm on the road (with a 9,600bps connection!).
I did not want to have to log onto PPRuNe to see the e-mails. I wanted to manage them from a site such as:
mail2web
On that site you can view and delete e-mails just like Hotmail - only simpler.
But to do that you have to know the address of the mail server(s). And they were not forthcoming when the mail facility was introduced. Something to do with revenue I suppose....