Jetpack unknown error & connection issues

I am having a number of issues with Jetpack on my wordpress.com site. On my dashboard I get an error saying “Jetpack can’t communicate with your site”. When I click “Learning how to fix”, it says to disconnect and reinstall Jetpack. But when I follow those instructions, I get an error that says “Please login directly to disconnect from your account”, even though I am already logged in. Under “Settings>Manage Connection” if I try to initiate a manual sync it says “The Jetpack site is inaccessible or returned an error: server error. requested method jetpack.jsonAPI does not exist. [-32601]”. When I click “Diagnose a connection problem” it says “Unkown Error”.

I also cannot access my pages or old posts via the dashboard (they are all imported from a previous site, and appear on the website, but when I click “Pages” on the Dashboard it says “You haven’t published any pages yet”), and there is an error message at the top of the page that says “Jetpack can’t communicate with your site because your site isn’t connected”

I’ve been struggling with this for a few days and am unclear what to do next. Any help would be greatly appreciated!

The page I need help with: [log in to see the link]