[jcifs] Why is this exception thrown from time to time?

[gruizf at credomatic.com]

The following exception occurs every now and then, though it seems the
users successfully log-in anyway.

[5/22/06 16:30:20:833 CST] 22f0651c WebGroup      E SRVE0026E: [Servlet
Error]-[Filter [NtlmHttpFilter]: filter is unavailable.]:
jcifs.smb.SmbException:
jcifs.util.transport.TransportException: Transport3 timedout waiting for
response to
SmbComSessionSetupAndX[command=SMB_COM_SESSION_SETUP_ANDX,received=false,errorCode=0,flags=0x0018,flags2=0xC003,signSeq=0,tid=0,pid=38476,uid=0,mid=226,wordCount=13,byteCount=123,andxCommand=0x75,andxOffset=184,snd_buf_size=16644,maxMpxCount=10,VC_NUMBER=1,sessionKey=0,passwordLength=24,unicodePasswordLength=24,capabilities=4180,accountName=azunigap,primaryDomain=COMBCOCR,NATIVE_OS=Windows
 2003,NATIVE_LANMAN=jCIFS]
      at jcifs.util.transport.Transport.sendrecv(Transport.java:74)
      at jcifs.smb.SmbTransport.send(SmbTransport.java(Compiled Code))
      at jcifs.smb.SmbSession.sessionSetup(SmbSession.java:264)
      at jcifs.smb.SmbSession.send(SmbSession.java:223)
      at jcifs.smb.SmbTree.treeConnect(SmbTree.java(Compiled Code))
      at jcifs.smb.SmbSession.logon(SmbSession.java(Compiled Code))
      at jcifs.smb.SmbSession.logon(SmbSession.java(Inlined Compiled Code))
      at jcifs.http.NtlmHttpFilter.negotiate(NtlmHttpFilter.java(Compiled
Code))
      at jcifs.http.NtlmHttpFilter.doFilter(NtlmHttpFilter.java(Compiled
Code))

What does it mean and why does it happen?

Thanks.