I use NamedPipes in c# (.Net 3.5 ). I want to write to threads for the client one read and the other for write.

I use NamedPipes in c# (.Net 3.5 ).
I want to write two threads for the client. One for read and the other for write.
Each thread has different NamedPipeClientStream.
The two threads try to Connect with some timeout.
The first client pass the Connect successfully but the other throw an IOException ("The semaphore timeout period has expired").
Why the second client can not Connect to the server?
How this code should be written?
Thanks.