Getting 422 (unprocessable entity) error while sending data from React to Mongodb

Question

I am getting 422 (Unprocessable Entity) error when I send form data form React to Mongo DB through Node.js (it's a MERN project) The error looks like

SignUp.jsx:24                       POST http://localhost:3000/signup 422 (Unprocessable Entity)
registerData                                         @ SignUp.jsx:24
callCallback                                         @ react-dom.development.js:4164
invokeGuardedCallbackDev                             @ react-dom.development.js:4213
invokeGuardedCallback                                @ react-dom.development.js:4277
invokeGuardedCallbackAndCatchFirstError              @ react-dom.development.js:4291
executeDispatch                                      @ react-dom.development.js:9041
processDispatchQueueItemsInOrder                     @ react-dom.development.js:9073
processDispatchQueue                                 @ react-dom.development.js:9086
dispatchEventsForPlugins                             @ react-dom.development.js:9097
(anonymous)                                          @ react-dom.development.js:9288
batchedUpdates$1                                     @ react-dom.development.js:26140
batchedUpdates                                       @ react-dom.development.js:3991
dispatchEventForPluginEventSystem                    @ react-dom.development.js:9287
dispatchEventWithEnableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay @ react-dom.development.js:6465
dispatchEvent                                       @ react-dom.development.js:6457
dispatchDiscreteEvent                               @ react-dom.development.js:6430

Although I have tried

 "proxy": {
    "/signup": {
      "target": "http://localhost:5000",
      "secure": false
    }
  },

(server is running on 5000 and client is on 3000)

still not working? This is the code for sending data

const registerData = async (e) => {
        e.preventDefault();
        const { name, email, phone, work, password, cpassword } = user;

        const response = await fetch('/signup', {
            method: "POST",
            headers: {
                "Content-Type": "application/json"
            },
            body: JSON.stringify({
                name, email, phone, work, password, cpassword
            })
        });

        const data = await response.json();

        if (data.status === 422 || !data) {
            window.alert("Invalid Registration");
            console.log("Invalid Registration");
        }
        else {
            window.alert("Registration Successful");
            console.log("Registration Successful");
        }


    };

Click here to show full project on GitHub.

I want to successfully send form data to DB and register user then login with that credentials