PullNotifcation Exchange Web Services “The Watermark is invalid” Exception?

I found the reason: My List of subscription was not thread safe. I added this to my code and it works fine: lock (_subList) { events = p.GetEvents(); }.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.