We recently experienced a very strange issue with our SIS integration middleware application. It has been working fine for months, but the enrollment (course membership) sync component has been failing recently with the following exception:
Exception: The underlying connection was closed: An unexpected error occurred on a send.
All the other 3 sync components (Term, Course and Person) are still working fine. We implemented the flat file data web push using the HttpWebRequest.GetRequestStream() method in C#. Bb Support states that there were no environmental changes that could cause the connection issue, and they suggested using UploadDataAsync() method. However, we couldn't get this method to work, either. Interestingly, we can still post the flat file data using 'curl'.
Has anyone used the UploadDataAsync() method? Any suggestions or sample code would be much appreciated.