The current problems and some questions

It's impossible to sync up like this, and I've tried manual backup since the beginning, but after I went into X, it says that the page I couldn't find. So I tried another Google account, and the other one worked well. But the problem is that bookmarks and like are not all synchronized. Is there a limit to the number of syncs, or is it impossible to sync too old? I'm not sure.

Feedback) And then the error keeps popping up and the page stops working. It says, "Application error: a client-side exception has accumulated (see the browser console for more information)." It keeps stopping while trying to do something or sync.