Incoming client connection failed to establish. Over the past %1 minutes Lync Server has experienced incoming connection ...

Incoming client connection failed to establish.

Over the past %1 minutes Lync Server has experienced incoming connection failures %2 time(s). The error code of the last failure is 0x%3 (%4) while handling a connection from host "%5".
Cause: This can occur if the connection attempt by the client was rejected due to the client's failure to provide appropriate credentials, or failure to complete TLS negotiation, because the client dropped the connection before it was completed, or due to high load on the server.
Resolution:
Verify the connection came from a trustworthy client.