(node:30144) UnhandledPromiseRejectionWarning: TypeError: callback is not a function
 at promise.then.err (/home/incarnus/saran/incarnus-master/incarnus/node_modules/mongoose/lib/connection.js:413:53)
 at <anonymous>
 at process._tickCallback (internal/process/next_tick.js:189:7)
(node:30144) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:30144) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
(node:30144) UnhandledPromiseRejectionWarning: MongoNetworkError: failed to connect to server [172.31.14.248:27017] on first connect [MongoNetworkError: connection 0 to 172.31.14.248:27017 timed out]
 at Pool.<anonymous> (/home/incarnus/saran/incarnus-master/incarnus/node_modules/mongodb/node_modules/mongodb-core/lib/topologies/server.js:503:11)
 at emitOne (events.js:116:13)
 at Pool.emit (events.js:211:7)
 at Connection.<anonymous> (/home/incarnus/saran/incarnus-master/incarnus/node_modules/mongodb/node_modules/mongodb-core/lib/connection/pool.js:326:12)
 at Object.onceWrapper (events.js:317:30)
 at emitTwo (events.js:126:13)
 at Connection.emit (events.js:214:7)
 at Socket.<anonymous> (/home/incarnus/saran/incarnus-master/incarnus/node_modules/mongodb/node_modules/mongodb-core/lib/connection/connection.js:256:10)
 at Object.onceWrapper (events.js:313:30)
 at emitNone (events.js:106:13)
 at Socket.emit (events.js:208:7)
 at Socket._onTimeout (net.js:422:8)
 at ontimeout (timers.js:498:11)
 at tryOnTimeout (timers.js:323:5)
 at Timer.listOnTimeout (timers.js:290:5)
(node:30144) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)