Pass json data to spring boot backend

I am completly new to spring boot. I am now trying to pass a registration form data(json format) from vue frontend to spring boot backend, but the backend always show the receiving data is null. How should I correctly receive the data?

RegistrationController.java

package com.example.demo.controller;

import com.example.demo.result.Result;
import com.example.demo.pojo.newUser;

//import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;


@RestController
public class RegistrationController {
    @CrossOrigin
    @PostMapping(value = "api/registration")
    @ResponseBody
    public Result registration(@RequestBody NewUser user) {
        System.out.println("###CompanyName: "+ user.getCompanyName());
        return new Result(200);
    }
}

NewUser.java

package com.example.demo.pojo;

public class NewUser {
    private String CompanyName;

    public String getCompanyName() {
        return CompanyName;
    }

    public void setCompanyName(String CompanyName) {
        this.CompanyName = CompanyName;
    }

}

Registration.vue

<template>
    <Form @submit="onSubmit" :validation-schema="schema">
      <span class="lblMandatory">* </span><span class="lblExplanatoryNote">This is a mandatory field and data must be provided.</span>

      <div class="form-group">
        <span class="lblSectionField">Company Name <span class="lblMandatory">*</span></span>
        <Field name="CompanyName" class="form-control"/>
        <ErrorMessage name="CompanyName" class="ErrorMessage"/>
      </div>
        <button class="btn btn-primary" type="submit">Submit</button>
    </Form>
  </div>
</template>

<script>
import axios from 'axios'

  export default {
    data(){
      return{

      }
    },
    methods: {
      onSubmit(values) {
        axios.post('registration', values)
        .then(successResponse => {
          console.log(successResponse.data.code)
          console.log(values)
            if (successResponse.data.code === 200) {
              alert("application success")
              this.$router.replace({name: 'home'})
            }
            else{
              alert("application failed")
            }
          })
          .catch(failResponse => {
            console.log(failResponse)
          })

      }
    }
  }
</script>

But in my spring boot backend terminal it shows: ###CompanyName: null

I edit the code shorter which only contain company name, which is still null. result