Connection pool has been idle for longer than the host timeout

During replication initial synch from primary to secondary, shows this message in mongod.log — "Dropping all pooled connections to mongo-repl-3:27017 due to NetworkInterfaceExceededTimeLimit: Connection pool has been idle for longer than the host timeout
", why this message showing? is anything to do with it?

Have you got the answers? I have also observed the same issue.