Unhandled Promise Rejection Network Error in React Native

Question

I want to post data from frontend which used React Native to the mongoDB database. This is my react native code and i used axios. Below function is called when user press saveButton.

const saveButton = async () =>{
        console.log("save button");
        const newUser = {name,role, email,contact,address,picture}
        console.log(newUser);
        if(name&&role&&email&&contact&&address&&picture)
        {
            await axios.post("http://localhost:8070/user/add",newUser).then(()=>{
                console.log("Saved data......!")
                setname("");
                setrole("")
                setcontact("");
                setemail("");
                setaddress("");
                setpicture("");
                setsaved(true);
            })
        }else{
            console.log("Enter all the fields")
        }
      } 

Unfortunately, there is an error called,

[Unhandled promise rejection: Error: Network Error]
at node_modules\event-target-shim\dist\event-target-shim.js:818:20 in EventTarget.prototype.dispatchEvent
at node_modules\react-native\Libraries\Network\XMLHttpRequest.js:609:10 in setReadyState
at node_modules\react-native\Libraries\Network\XMLHttpRequest.js:396:6 in __didCompleteResponse
at node_modules\react-native\Libraries\vendor\emitter\_EventEmitter.js:135:10 in EventEmitter#emit
at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:414:4 in __callFunction
at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:113:6 in __guard$argument_0
at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:365:10 in __guard
at node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:112:4 in callFunctionReturnFlushedQueue

When I checked this through postman, it worked. But in react native, this error occurred. Is anyone can help me to solve this error? Thank you!