Email Subscriber is not receiving Confirmation Email

My email subscriber checked every one of her folders in her email (spam, inbox, etc.) and still can’t locate an email that came from my site. I have Jetpack installed. It’s been 24 hours since she subscribed. I did a test this morning for one of my email addresses and it worked for me.

Is there anything I can do as the Administrator to add them on list? I read that email confirmations are only sent once. We tried adding her email multiple times to no avail. Please assist. Thanks!