Cypress failing test due to CORS?

I have a simple test that fails due to CORS and I'm unsure how to fix it:

    it("Visits home", () => {
        cy.visit("http://localhost:3000");
    });

This is the error:

  1) Test
       Visits the home page:
     SecurityError: Blocked a frame with origin "http://localhost:3000" from accessing a cross-origin frame.

Go to cypress.json and add:

chromeWebSecurity: false

Setting chromeWebSecurity to false in Chrome-based browsers allows you to do the following:

• Display insecure content
• Navigate to any superdomain without cross-origin errors
• Access cross-origin iframes that are embedded in your application