Check the conduits in your Hot Sync Manager it is probably failing on the email one. Disable all conduits that are not flagged as Maximzier and try again.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .