'Connection: close' in Step 2

I'm using jcifs v1.2.6 and i'm getting a weird response from server on step 2 
of the handshaking protocol.
The server is closing the connection. Here is the HTTP header response obtained 
for the server 

HTTP/1.1 401 Unauthorized
Server: WebSphere Application Server/5.0
WWW-Authenticate: NTLM 
TlRMTVNTUAACAAAADAAMADAAAAAFAoEADoez7m68Lh4AAAAAAAAAADYANgA8AAAARABFAFMAMAAwADAA
AgAMAEQARQBTADAAMAAwAAEAHgBKAEMASQBGAFMAMQA2ADAAXwAxADIAOQBfAEQAMQAAAAAA
Content-Language: es-ES
Transfer-Encoding: chunked
Connection: close

As you can see, server handles HTTP 1.1. 
I'm using the NtlmHttpFilter as is, without any modification.

Any idea on why the server is adding the 'connection: close' header to the 
response?

Thanks