강의 잘보고있습니다 질문하나만해도될까요??ㅠ

안녕하세요 강의 보면서 따라하고있는 있는데요ㅠㅠ

 { MongooseServerSelectionError: connection <monitor> to 52.74.108.133:27017 closed

[0]     at new MongooseServerSelectionError (D:\john ann\boilerplate-mern-stack\node_modules\mongoose\lib\error\serverSelection.js:22:11)

[0]     at NativeConnection.Connection.openUri (D:\john ann\boilerplate-mern-stack\node_modules\mongoose\lib\connection.js:823:32)

[0]     at Mongoose.connect (D:\john ann\boilerplate-mern-stack\node_modules\mongoose\lib\index.js:333:15)

[0]     at Object.<anonymous> (D:\john ann\boilerplate-mern-stack\server\index.js:18:26)

[0]     at Module._compile (internal/modules/cjs/loader.js:776:30)

[0]     at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)

[0]     at Module.load (internal/modules/cjs/loader.js:653:32)

[0]     at tryModuleLoad (internal/modules/cjs/loader.js:593:12)

[0]     at Function.Module._load (internal/modules/cjs/loader.js:585:3)

[0]     at Function.Module.runMain (internal/modules/cjs/loader.js:829:12)

[0]     at startup (internal/bootstrap/node.js:283:19)

[0]     at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)

[0]   message: 'connection <monitor> to 52.74.108.133:27017 closed',

[0]   name: 'MongooseServerSelectionError',

[0]   reason:

[0]    TopologyDescription {

[0]      type: 'ReplicaSetNoPrimary',

[0]      setName: null,

[0]      maxSetVersion: null,

[0]      maxElectionId: null,

[0]      servers:

[0]       Map {

[0]         'youtubeclone-shard-00-00-s85lt.mongodb.net:27017' => [ServerDescription],

[0]         'youtubeclone-shard-00-01-s85lt.mongodb.net:27017' => [ServerDescription],

[0]         'youtubeclone-shard-00-02-s85lt.mongodb.net:27017' => [ServerDescription] },

[0]      stale: false,

[0]      compatible: true,

[0]      compatibilityError: null,

[0]      logicalSessionTimeoutMinutes: null,

[0]      heartbeatFrequencyMS: 10000,

[0]      localThresholdMS: 15,

[0]      commonWireVersion: null },

[0]   [Symbol(mongoErrorContextSymbol)]: {} }

서버에 접속하는건 되는데요 시간이 지나거나 새로고침을 누르면 자꾸 이런 오류가 뜨네요 ㅠㅠ왜이러는걸까요?

그리고 로그인하고 들어가서 로그아웃을 누를경우 로그아웃이 되야하는건가요? 저만 안되는거같아서요!