crontab -l
# fuu openssl
10 0 * * * yum -y update openssl openssl-devel gnutls > /dev/null 2>&1

*also needs restarting apache/nginx/php-fpm

The cache contains information about errors that occur during the connection process. Some errors are considered “blocking.” If too many of these occur successively from a given host without a successful connection, the server blocks further connections from that host. The max_connect_errors system variable determines the number of permitted errors before blocking occurs.

Read more about host cache.

To unblock the host use:
mysqladmin flush-hosts
To get rid of the blocks, set in my.cnf:
skip-name-resolve