Host 'host_name' is blocked because of many connection errors. Unblock with 'mysqladmin flush-hosts'
I was able to resolve my issue with following:

# mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 216305
Server version: 5.1.73-log Source distribution

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owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql&gt; SET GLOBAL max_connect_errors=10000;
Query OK, 0 rows affected (0.00 sec)

mysql&gt; Bye
# 


I'm not entirely sure, if that actually what addressed my issue, however after above SQL statement, my app started to work (without being blocked anymore).