The server was unable to find a free connection %2 times in the last %3 seconds. This indicates a spike in network traffic. ...

The server was unable to find a free connection %2 times in the last %3 seconds.  This indicates a spike in network traffic.  If this is happening frequently, you should consider increasing the minimum number of free connections to add headroom.  To do that, modify the MinFreeConnections and MaxFreeConnections for the LanmanServer in the registry.