Why might `setError` in React Hook Form not be triggering validation errors?

The `setError` function might not be triggering validation errors if the form is not properly registered with `useForm`. Ensure you've called `const { register, handleSubmit, formState: { errors }, setError } = useForm()`. Also, check if you're calling `setError` *before* the component has fully mounted, or within a conditional that prevents it from running. Finally, ensure the field name you're passing to `setError` exactly matches the `name` attribute used in the `register` function.