The ThreatX portal allows you to easily block an IP Address or a CIDR range by adding it to blacklist.
As first step you will have to log into the ThreatX portal at x.threatx.io and access
Settings > IWAF from the navbar.
Select the Blacklist tab and click on Add Entry in the top right corner.
This will present you with a pop to add the IP address or the CIDR range. Add and click Submit.