How to verify domain ownership for a new user?

Are there products or ways to verify that a user's email address and their corporate URL are connected?

Here's the use case: 1. User signs up for a product 2. User submits their email and company's website 3. We need to verify if that company website is associated with that email.

We thought it could be as simple as $email == $URL

BUT we're seeing many cases where the email sending domain is different than the company's URL

How might one do this?