SessionOptions.HostName is not set

With sessionOptions
    .Protocol = Protocol.Sftp
    .HostName = "xxxxx"
    .UserName = "xxxx"
    .Password = "xxxxxxxx"
    .SshHostKeyFingerprint = "ssh-rsa 1024 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
End With
 
Using mySession As Session = New Session
    ' Connect
    mySession.Open(mySessionOptions)
End Using