My guess would be your host's server is the issue, not the JetPack or YOUR connection.Especially if other sites load and work well for you. Use tools like WebPagetest - Website Performance and Optimization Test o Website speed test to see how the site loads. WordPress has a high overhead in terms of load times and backend stuff going on - and adding the Dashboard interface on top of that for editing the site gives you a data intensive situation.
Does the time out happen when editing pages? posts? Uploading files? Using or editing with a specific plugin? Plugins add functionality, but they can also wreak havoc with load times and page speeds. And the more plugins you have, the greater the chance of conflicts and problems.
I am having the same problem! It wasnt always like this, it randomly times out, it will work for about 30 seconds then time out for 2 minutes, internet speed is fine everything else works normally. please help