The plugin used to have a tool to blacklist IP addresses but I removed that code when the company released the full-featured firewall CloudProxy WAF [1] that acts as a shield against a big list of security threats, and at the same time optimize your website to load faster and behave better.
If you want to stay with the free software then you can take a look to the WordPress recommended security plugins [2], you can also find good plugins searching the words IP [3], Block IP [4], and Blacklist [5].
[1] https://sucuri.net/website-firewall/
[2] https://codex.www.ads-software.com/Brute_Force_Attacks#Plugins
[3] https://www.ads-software.com/plugins/tags/ip
[4] https://www.ads-software.com/plugins/tags/block-ip
[5] https://www.ads-software.com/plugins/tags/blacklist
