Error: Connecton closed

I am working in my app. But after some times, it emits error like this. What is the problem?How can I remove this?

App running at: http://localhost:3000/
I20160723-23:01:01.621(5.75)? ** You’ve set up some data subscriptions with Meteor.publish(), but
I20160723-23:01:01.622(5.75)? ** you still have autopublish turned on. Because autopublish is still
I20160723-23:01:01.623(5.75)? ** on, your Meteor.publish() calls won’t have much effect. All data
I20160723-23:01:01.623(5.75)? ** will still be sent to all clients.
I20160723-23:01:01.623(5.75)? **
I20160723-23:01:01.623(5.75)? ** Turn off autopublish by removing the autopublish package:
I20160723-23:01:01.623(5.75)? **
I20160723-23:01:01.623(5.75)? ** $ meteor remove autopublish
I20160723-23:01:01.624(5.75)? **
I20160723-23:01:01.624(5.75)? ** … and make sure you have Meteor.publish() and Meteor.subscribe() calls
I20160723-23:01:01.624(5.75)? ** for each collection that you want clients to see.
I20160723-23:01:01.624(5.75)?
Unexpected mongo exit code 14. Restarting.
W20160723-23:01:30.275(5.75)? (STDERR) Error: connection closed
W20160723-23:01:30.276(5.75)? (STDERR) at [object Object]. (/home/kiran/.meteor/packages/npm-mongo/.1.4.43.yljolx++os+web.browser+web.cordova/npm/node_modules/mongodb/lib/mongodb/connection/server.js:610:98)
W20160723-23:01:30.276(5.75)? (STDERR) at [object Object].emit (events.js:92:17)
W20160723-23:01:30.276(5.75)? (STDERR) at [object Object]. (/home/kiran/.meteor/packages/npm-mongo/.1.4.43.yljolx++os+web.browser+web.cordova/npm/node_modules/mongodb/lib/mongodb/connection/connection_pool.js:171:15)
W20160723-23:01:30.276(5.75)? (STDERR) at [object Object].emit (events.js:98:17)
W20160723-23:01:30.277(5.75)? (STDERR) at Socket. (/home/kiran/.meteor/packages/npm-mongo/.1.4.43.yljolx++os+web.browser+web.cordova/npm/node_modules/mongodb/lib/mongodb/connection/connection.js:550:12)
W20160723-23:01:30.277(5.75)? (STDERR) at Socket.emit (events.js:95:17)
W20160723-23:01:30.277(5.75)? (STDERR) at TCP.close (net.js:466:12)