Timed out waiting for client to present validation cookie Over the past %1 minutes Lync Server has disconnected client(s) ...

Timed out waiting for client to present validation cookie

Over the past %1 minutes Lync Server has disconnected client(s) %2 time(s) because of timing out waiting for cookie to be presented. The last such client which was disconnected is "%3"
Cause: This can occur if client does not present a validation cookie within 20 seconds of getting connected
Resolution:
Check to make sure that the connection came from a trustworthy client. This could indicate an attack being mounted by a rogue client.