Hi there,
Jetpack can’t affect your site if you’ve deleted it. But if you deleted Jetpack without disconnecting it first, Jetpack Monitor will continue checking the site, and will send you notifications if it can’t find the site online.
But there’s no way those emails can cause your site to crash – they’re being sent from our servers in response to a periodic ping we send to your site, and don’t use any resources on your server. Rather, you’re receiving those emails because the site has crashed – Monitor is still just doing what it was designed to do: checking your site, and letting you know when it cannot reach your site.
As the Jetpack connection for that site is not currently active I’ve disabled Monitor, but if you’re experiencing downtime on your site, it’s either another plugin causing it, or an issue on your server, so it’s best to contact your hosting provider for help with that – they might be able to get you more information on exactly what’s going on from the server logs.
