LinuxホストをSnapCenterに正しく追加できない

環境

• NetApp SnapCenterサーバ4.X
• SnapCenter for Linuxプラグイン

問題

SnapCenterにLinuxホストを追加すると、ホストが正しく追加されず、SnapManager Webログに次のエラーが表示されます。

YYYY-MM-DDThh:mm:ss.+00:00 INFO  SnapManagerWeb PID=[11220] TID=[115] Creating new SSH client
YYYY-MM-DDThh:mm:ss.+00:00 INFO  SnapManagerWeb PID=[11220] TID=[115] Setting ssh connection timeout to 600 seconds
YYYY-MM-DDThh:mm:ss.+00:00 INFO  SnapManagerWeb PID=[11220] TID=[115] Connecting to the remote system XX.YY.ZZ.XX using SSH
YYYY-MM-DDThh:mm:ss.+00:00 ERROR SnapManagerWeb PID=[11220] TID=[115] Failed to connect to the host XX.YY.ZZ.XX. Verify connectivity to the host.
Exception: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond XX.YY.ZZ.XX:22
YYYY-MM-DDThh:mm:ss.+00:00 ERROR SnapManagerWeb PID=[11220] TID=[115] StackTrace:   at System.Net.Sockets.Socket.InternalEndConnect(IAsyncResult asyncResult)
  at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
  at Renci.SshNet.Session.SocketConnect(String host, Int32 port)
  at Renci.SshNet.Session.Connect()
  at Renci.SshNet.BaseClient.Connect()
  at SnapManagerSSH.SmSSH.GetFingerPrint()
YYYY-MM-DDThh:mm:ss.+00:00 DEBUG SnapManagerWeb PID=[11220] TID=[115] GetHostSignature: Exit