Customer Not Receiving Contact Form Emails

I’m having trouble with

Customer not receiving contact form emails even though notifications are set up correctly… test emails to their address bounce back.

Working in

Wix Studio Editor

What I’m trying to do

Ensure that when the contact form is submitted, both I and my customer receive email notifications.

What I’ve tried so far

Verified email notifications are correctly set up, checked spam/junk folders, tested sending emails to the customer’s address (which bounced).

Extra context

Customer’s email is correct, automation settings are properly configured…

It would be great if someone could explain, how to fix
Thanks!!