Console show this error in the picture below

I am trying to solve cors error at vue.config.js but still not working

module.exports = {
  devServer: {
    proxy: 'http://localhost:3000',
  }
}

this Axios post API method

  methods: {
    // send data
    async signup() {
      if (this.name == "" || this.email == "" || this.password == "") {
        return true;
      } else {
        document.querySelector("button").setAttribute("type", "button");
        let result = await axios.post("http://localhost:3000/user", {
          name: this.name,
          email: this.email,
          password: this.password,
        });
    
        if (result.status == 201) {
          localStorage.setItem("user-information", JSON.stringify(result.data));
          this.$router.push({ name: "Home" });
        }
      }
    },
  },