http://localhost:8080/topicos not found 404

https://cursos.alura.com.br/forum/topico-http-localhost-8080-topicos-da-erro-109818 Encontrei esse tópico no forum, porem não deu certo as alterações que fiz com base na solução

This application has no explicit mapping for /error, so you are seeing this as a fallback.

Wed Sep 08 21:16:49 BRT 2021
There was an unexpected error (type=Not Found, status=404).
No message available

package br.com.alura.forum;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class ForumApplication {

    public static void main(String[] args) {
        SpringApplication.run(ForumApplication.class, args);
    }

}

package br.com.alura.forum.controller;


import java.util.Arrays;
import java.util.List;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import br.com.alura.forum.modelo.Curso;
import br.com.alura.forum.modelo.Topico;

@RestController
public class TopicosController {

    @RequestMapping("\topicos")
    @ResponseBody
    public List<Topico> lista(){
        Topico topico = new Topico("Duvida" , "duvida com spring", new Curso("Spring boot", "Programação"));

        return Arrays.asList(topico, topico, topico);
    }

}