Emails stopped working

I recommend contacting the folks behind Jetpack about this via https://jetpack.com/contact-support/

Thanks, will do. Worth contacting our host (Bluehost) about it, too, or is it likely a Jetpack issue?

No, the emails are sent from the WordPress.com servers by way of Jetpack, so if the emails aren’t being sent there’s likely either an issue on the Jetpack end or with your site’s configuration, but most likely not the server or your hosting provider.

Got it — thanks.

You’re welcome!