Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 97393
Server version: 5.5.45-enterprise-commercial-advanced MySQL Enterprise Server - Advanced Edition (Commercial)
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> mysqladmin flush-hosts -> ; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'mysql admin flush-hosts' at line 1 mysql>
I believe that command only works with root level mysql permissions.
Restarting the mysql service will flush this condition.
Functionally, mysql has almost like a firewall configuration - if it receives I think 10 failed logins from one IP address, subsequent connections from that IP address will experience the blocking you have encountered.
What is generating the failed connections to mysql? Did someone change the credentials inside a connector?