C2C mongosyncc is not starting as

Have configured 2 replicaset and tried to configure cluster2cluster sync using mongosync. Mongosync process is not starting and running for log time. Can see below entries in logfile with verbosity"TRACE". Please advise.

:“Server heartbeat failed: &{DurationNanos:48611345 Duration:48.611345ms Failure: connection(server1:27040[-18]) incomplete read of message header: context canceled: connection(server1:27040[-18]) incomplete read of message header: context canceled ConnectionID:server1:27040[-18] Awaited:true}”}

#cat mongosync.conf
cluster0: “mongodb://clusteradmin:welcome@server1:27017,server2:27017,server3:27017”
cluster1: “mongodb://clusteradmin:welcome@server1:27040,server2:27040,server3:27040”
logPath: “/log/mongosync”
verbosity: “TRACE”