Problemas nos métodos com postman | Node.js: API Rest com Express e MongoDB

Quando faço qualquer requisição pelo postman aparece o erro

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    <title>Error</title>
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    <pre>SyntaxError: Unexpected end of JSON input<br>    at JSON.parse (<anonymous>)<br>    at createStrictSyntaxError (C:\Alura\Formacoes\4-nodeJS\API-rest\node_modules\body-parser\lib\types\json.js:160:10)<br>    at parse (C:\Alura\Formacoes\4-nodeJS\API-rest\node_modules\body-parser\lib\types\json.js:83:15)<br>    at C:\Alura\Formacoes\4-nodeJS\API-rest\node_modules\body-parser\lib\read.js:128:18<br>    at AsyncResource.runInAsyncScope (node:async_hooks:202:9)<br>    at invokeCallback (C:\Alura\Formacoes\4-nodeJS\API-rest\node_modules\raw-body\index.js:231:16)<br>    at done (C:\Alura\Formacoes\4-nodeJS\API-rest\node_modules\raw-body\index.js:220:7)<br>    at IncomingMessage.onEnd (C:\Alura\Formacoes\4-nodeJS\API-rest\node_modules\raw-body\index.js:280:7)<br>    at IncomingMessage.emit (node:events:539:35)<br>    at endReadableNT (node:internal/streams/readable:1345:12)</pre>
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Mas pelo navegador funciona, acho que tem algum erro que não consigo perceber :( Meu código

import express from "express";

const app = express();

app.use(express.json())

const books = [
  {id: 1, "title":"Senhor dos Anéis"},
  {id: 2, "title":"O Hobbit"}
]

app.get('/', (req, res) => {
  res.status(200)
  .send("Curso de node");
})

app.get('/livros', (req, res) => {
  res.status(200)
  .json(books);
})

app.get('/livros/:id', (req, res) => {
  let index = searchBook(req.params.id)
  res.json(books[index])
})


app.post('/livros', (req, res) => {
  books.push(req.body);
  res.status(201)
  .send('Livro cadastrado com sucesso')
})


app.put('/livros/:id', (req, res) => {
  let index = searchBook(req.params.id);
  books[index].title = req.body.title;
  res.json(books)
})

function searchBook (id){
  return books.findIndex(book => book.id == id);
}

export default app