how to fix cors error in react and spring web application?

How to fix CORS error in my React and spring application.

I've implemented a simple method to get list of users. I've tested this endpoint using postman. Now I'm fetching this list from my react js application using fetch API. I've added the @CrossOrigin annotation in my spring backend. I've also added a proxy to my package.json file in my React application.

React JS code :-

import React from 'react';
import { Component } from 'react';

class DropDownUsers extends Component {
  state = {
    users : [],
    selectedUser : "",
    validationError : ""
  }

  componentDidMount() {

   fetch("http://localhost:8080/api/users")
    .then(data => {
      let usersFromApi = data.map(user => {
        return {
          value : user,
          display : user
        }})
      this.setState({ users : [{value: '', display: '(Choose the user)'}].concat(usersFromApi)});
    })
      .then((response) => {
        return response.json();
      })
      .catch(error => {
        console.log(error);
      });
  }

  render() {
    return (
      <div>
        <select value={this.state.selectedUser}
                onChange={(e) => this.setState({selectedUser: e.target.value})}
         >
         {this.state.users.map((user) => <option key={user.value} value={user.value}> {user.display}</option>)}
        </select>
        <div style={{color:'red',marginTop:'5px'}}>
          {this.state.validationError}
        </div>
      </div>
    )
  }
}

export default DropDownUsers;

Error message :-

Access to fetch at 'http://localhost:8080/api/users' from origin 'http://localhost:3001' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled

Spring Config file :-

public ConfigurableServletWebServerFactory servletContainer() {
        final TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();

        if (ajpEnabled) {
            factory.setProtocol("AJP/1.3");

            factory.addConnectorCustomizers(connector -> {
                connector.setSecure(false);
                connector.setScheme("http");
                connector.setAllowTrace(true);
                connector.setPort(8009);
            });
        }

        return factory;
    }

Spring Controller :-

@Slf4j
@EnableLogging
@CrossOrigin(origins = "http://localhost:3001")
@Path("/users")
public class ListOfUsers {

    @Autowired
    DAO DAO;

    @GET
    @Produces(APPLICATION_JSON)
    public Response execute(@Valid ListOfUsersBean listOfUsersBean) {

        final Optional<List<ListOfUsersBean>> user = DAO.getTotalListOfUsers();
        return status(SC_OK).entity(user).build();
    }

    @Bean
    public WebMvcConfigurer corsConfigurer() {
        return new WebMvcConfigurerAdapter() {
            @Override
            public void addCorsMappings(CorsRegistry registry) {
                registry.addMapping("/**").allowedOrigins("*");
            }
        };
    }

}

I want to list the users in a dropdown menu. Any help would be appreciated.