How can I be alerted to an incorrect email address?

I would like to set up my forms so that when a customer completes the form and their email address is incorrect, it will not allow them to submit it unless it is amended? 

Hi kate123, 

Thanks for contacting us.

You can try to use E-mail Validator widget. I think this is what you are looking for. This widget will make sure you always have a correct and valid email address submitted from your form users. This widget also makes sure that a valid email is used on your form through a pass-code verification process.

Do let us know if you need further assistance.

Regards.