We have a client that initializes a number of subscriptions to different items. Sometimes during this process, we receive and error on the client that states "The underlying connection was closed. The connection was closed unexpectedly". Reviewing the Lightstreamer log file we see the following error code 38 being reported with a Sync Error.

17-Feb-12 14:12:18,261|INFO |LightstreamerLogger.requests |FOR PUMPS PARKING DESTROYER|Closed session Sfde77fce01081e71T0851448 with internal cause code: 38
17-Feb-12 14:12:20,383|INFO |LightstreamerLogger.requests |SERVER POOLED THREAD 9 |Serving request: /lightstreamer/control.txt --> LS_session=Sfde77fce01081e71T0851448&LS_op=destroy from xxx.xx.xxx.xxx:2650
17-Feb-12 14:12:20,383|INFO |LightstreamerLogger.requests |SERVER POOLED THREAD 9 |Destroying session: Sfde77fce01081e71T0851448 from xxx.xx.xxx.xxx:2650
17-Feb-12 14:12:20,383|INFO |LightstreamerLogger.requests |SERVER POOLED THREAD 9 |Sync error: Can't find session from xxx.xx.xxx.xxx:2650

Note that the IP addresses have been removed for sanitization reasons. Could you please help us understand what might be happening and possibly what internal cause code 38 might be? For your information we are using Presto 4.0.1 version of Lightstreamer running on a windows 2008 R2 server and the client is currently running on windows XP using a C# implementation for both the client and Data Adapters.

Thanks in advance for the help.