Firewall challenges availability issues
Orinal source post by Cloudflare
Nov 12, 14:12 UTC
Resolved - Cloudflare is aware that a scheduled maintenance change that may have caused an unexpected behaviour preventing end users from being able to pass Captcha Challenge or Javascript Challenges.
The impact was between 14:12 - 15:50 UTC and during this time end clients may not been able to immediately pass the challenge page on the first attempt, resulting in a drop of traffic to the origin server.