ERROR 1129 (HY000): Host 'host_name' is blocked because of many connection errors.
Unblock with 'mysqladmin flush-hosts'

A Host is Blocked error occurs when your server has received too many interrupted connection requests for your location. The default value of the max_connect_errors system variable is 100 connections in a short period of time.

If you are getting this error, ensure that your queries are not timing out and that your network connection is stable.