Error on mongos server

Firstly,I am new to mongodb. when we executed the below command on mongos server.

/usr/bin/mongos --configdb X.X.X.1:20001,X.X.X.2:20002,X.X.X.3:20003 --port 27017 --chunkSize 1

we are getting the below error:

2014-12-01T14:40:24.947+0300 [Balancer] SyncClusterConnection connecting to [X.X.X.1:20001]
2014-12-01T14:40:24.947+0300 [Balancer] SyncClusterConnection connecting to [X.X.X.2:20002]
2014-12-01T14:40:24.948+0300 [Balancer] SyncClusterConnection connecting to [X.X.X.3:20003]
2014-12-01T14:40:24.957+0300 [Balancer] scoped connection to X.X.X.1:20001,X.X.X.2:20002,X.X.X.3:20003 not being returned to the pool
2014-12-01T14:40:24.957+0300 [Balancer] caught exception while doing balance: error checking clock skew of cluster X.X.X.1:20001,X.X.X.2:20002,X.X.X.3:20003 :: caused by :: 13650 clock skew of the cluster X.X.X.1:20001,X.X.X.2:20002,X.X.X.3:20003 is too far out of bounds to allow distributed locking.

Kindly let us know what it meant by. weather it is properly connected with config server or not?