How to get the Amplify Data example to work

I’m building an app using React on Amplify and I’m adding a database. I followed the instructions here. List seems to work and returns an empty array. But, create is not working with no error. I’m using NoSQL Workbench and I see the tables but no data. With no error to go on I don’t know what to try next.

import { useState, useEffect } from "react";
import { generateClient } from "aws-amplify/data";

const client = generateClient();

const TodoList = () => {
  const [todos, setTodos] = useState([]);

  const fetchTodos = async () => {
    const { data: items, errors } = await client.models.Things.list();
    console.log(items, errors);
    setTodos(items);
  };

  useEffect(() => {
    void fetchTodos();
  }, []);

  const createTodo = async () => {
    try {
      await client.models.Things.create({
        content: window.prompt("Todo content?"),
        isDone: false,
      });

      void fetchTodos();
    } catch (error) {
      console.error(error);
    }
  }

  return (
    <div>
      <button onClick={createTodo}>Add new todo</button>
      <ul>
        {todos.map(({ id, content }) => (
          <li key={id}>{content}</li>
        ))}
      </ul>
    </div>
  );
}

export default TodoList;