I have a silverlight application it makes HTTPS request, it works fine when I am tracing the application with fiddler ON, But it throws Remote server not found error when I don't have fiddler running
I ran into this recently, in Fiddler Options->HTTPS I had 'ignore server certificate errors' checked. Unchecked that and Fiddler displayed a certificate error.
Ended up adding the code mentioned here http://social.msdn.microsoft.com/Forums/en-US/ncl/thread/43a933b8-e2b1-40a7-ac23-9bf3fc14b1f0