Background
We currently have a SilverLight form that posts data to a second common form that multiple applications use, which then runs the need business logic to place the data into a database.
We have several national and international offices where this form is used.
There is one office location (CO) where this form is consistently producing intermittent error messages and based off log data, it is only happening in this office.
Error Symptoms
Initially users will typically report that there is an error and when I log into their machine using MS Communicator, 80% of the time it would start working.
I started installing Fiddler on their machines to try and capture more information but 100% of the time I did that, the form started posting successfully. The users being resourceful, simply start Fiddler anytime the form doesn't post and it works fine.
I also asked users to go through Citrix which is hosted in the TX office and the form posts fine.
Error Details
I used OPNET to better monitor the traffic and I found that when user's simply open IE the authentication handshake fails. Client => Server = 401 Client <= Server = Authentication Token Client does not respond
When we use fiddler, the handshake is successful.
The error returned by SilverLight was a very generic [HttpWebRequest_WebException_RemoteServer] message.
Question
What would cause the handshake to work sometimes by itself, always with fiddler and CITRIX, and sometimes it doesn't.
