Unable to create a network share to a windows pc after some sucessfull logins using windows CE 6

Hello community.

We are encountering a strange behaviour using the network share of Windows CE 6.
First something about the application. It is written in c# and uses the .Net Compact Framework 3.5.
To establish a network share we use the Windows Function “WNetAddConnection3” and to close the share we use “WNetCancelConnection2”. The Program produces some measurement data and wants to transfer it to a server. Every time we want to transfer the data we establish a connection, copy the files and then terminate the network share (this was a request by our customer because he don’t want a permanent connection).
This function is working fine for many times, but after about 1000 established connections the login method changes and the server rejects the connection.
In the working connections the Bit “Extended Security Negotiation: Extended security negotiation is supported” from the SMB Protocol is set to 1. In the non working authentification this bit is set to 0.
The only way to get the SMB protocol working again is to reset the device. I added a Wireshark Capture of this behavior. The problem happens in the Packet “Session Setup AndX Request, NTLMSSP_NEGOTIATE”.
I hope soeone could help me with that problem.

Best regards,
Dirk

Is it possible that connection is not closed properly and it will stop working after some time?

As far as we can see it in our network trace, the connection is closed as always. The Problem is that this error occurs after 900 to 1000 successfull logins.

@DMankel, do you have another Toardex module, e.g. Colibri VFxx with WinCE 6? If yes, can you also try it with this module with the latest WinCE 6 image?
What is the error message returned when the connection cannot be established?
Do you see any error message on the debug serial port? Please enable WinCE debug messages:
http://developer.toradex.com/knowledge-base/enable-the-debug-messages
or use the debug message logger tool for PXA: http://developer.toradex.com/knowledge-base/debug-message-logger