ReactRedux获取网络请求失败

Question

我正在尝试从localhost获取：

export function fetchUsersFromAPI() {
    return(dispatch) => {
        dispatch(getUsers())
         fetch('https://localhost:3000/users')
      // fetch('https://192.168.0.2:3000/users/')  //< same error for this too
        .then(res => res.json())
        .then(json => dispatch(getUsersSuccess(json.results)))
        .catch(err => dispatch(getUsersFailure(err)))
    }
}

从浏览器访问https://192.168.0.2:3000/users或https://localhost:3000/users返回：

[{"id":1,"name":"Name1","color":"Green"},{"id":2,"name":"Name2","color":"Red"},{"id":3,"name":"Name3","color":"Yellow"}]

所以它已经在json。是否必须在Redux fetch中使用https而不是http？

我将err传递给我的减速机，所以我得到了：

"TypeError: Network request failed
    at XMLHttpRequest.xhr.onerror (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:15946:16)
    at XMLHttpRequest.dispatchEvent (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:18719:35)
    at XMLHttpRequest.setReadyState (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:18502:18)
    at XMLHttpRequest.__didCompleteResponse (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:18358:14)
    at http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:18453:45
    at RCTDeviceEventEmitter.emit (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:9351:35)
    at MessageQueue.__callFunction (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:8235:42)
    at http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:8051:15
    at MessageQueue.__guard (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:8206:9)
    at MessageQueue.callFunctionReturnFlushedQueue (http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=true&minify=false:8050:13)"

我做错了什么？如果我使用fetch('https://swapi.co/api/people/')则可行。请帮忙。