Javascript Module Import and Export not Working (Importing binding name is not found.)

I've scoured SO and the Web for answers, but have found nothing so far that has helped. When navigating to my test site (see below), I'm getting this error: Importing binding name 'Person' is not found.

From index.html:

<script type="module" src="js/person.js"></script>
<script type="module" src="js/script.js"></script>

From script.js:

import {Person} from '/js/person.js';

From person.js:

export class Person {
  constructor(
    firstName, lastName, email
  ){
    this.firstName = firstName;
    this.lastName = lastName;
    this.email = email;
  }

  setFirstName(firstName){
    this.firstName = firstName;
  }

  setLastName(lastName){
    this.lastName = lastName;
  }

  setEmail(email){
    this.email = email;
  }

}

All the documentation I've found appears to indicate that I'm doing this correctly, and yet I get the error. Any ideas, anyone?

UPDATE Everything works fine under Windows, but not using MacOS 12 in Safari, Firefox, or Chrome. Why?