Host key does not match configured key
I am totally new to this winscp and I have pull the files from the unix box using winscp
I have got below url to refer and code.
https://winscp.net/eng/docs/library_session_listdirectory#example
I have coded accordingly below is my code
 Try
            ' Setup session options
            Dim mySessionOptions As New SessionOptions
            With mySessionOptions
                .Protocol = Protocol.Sftp
                .HostName = TxtHost.Text
                .UserName = TxtUName.Text
                .Password = TxtPwd.Text
                .PortNumber = 22
                .SshHostKeyFingerprint = TxtKey.Text
            End With
            LblInfo.Text = LblInfo.Text & "Assigned Session Options" & vbNewLine
            Dim mySession As New Session
            Using mySession
                LblInfo.Text = LblInfo.Text & "Session declared " & vbNewLine
                mySession.Open(mySessionOptions)
                LblInfo.Text = LblInfo.Text & "Connected" & vbNewLine
                Dim directory As RemoteDirectoryInfo = mySession.ListDirectory(TxtSource.Text)
                LblInfo.Text = LblInfo.Text & "Setting Transfer Options " & vbNewLine
                Dim fileInfo As RemoteFileInfo
                LblInfo.Text = "-----------------------------------------------------"
                For Each fileInfo In directory.Files
                    'Console.WriteLine("{0} with size {1}, permissions {2} and last modification at {3}", _
                    'fileInfo.Name, fileInfo.Length, fileInfo.FilePermissions, fileInfo.LastWriteTime)
                    LblInfo.Text = LblInfo.Text & fileInfo.Name.ToString & " with size " & fileInfo.Length.ToString & ", permissions " & fileInfo.FilePermissions.ToString & " and last modification at " & fileInfo.LastWriteTime.ToString & vbNewLine
                    'lblinfo.Text = "copied file : " & vbNewLine
                Next
                LblInfo.Text = "-----------------------------------------------------"
            End UsingMy SshHostKeyFingerprint is like below format
ssh-rsa 1024 xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx
but when I try to open session I get below error
Host key does not match configured key "
ssh-rsa 1024 xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx"!
Where am I going wrong and someone help me getting it corrected asap