There were complaints for that IP: http://liveipmap.com/104.24.117.13
That is probably the reason for the blacklisting.
Anonymous proxy abuse at cloudflare, see passive DNS info: https://www.virustotal.com/en-gb/ip-address/104.24.117.13/information/

polonus

P.S. Sorry for the belated reaction, I was tracking in High Tatra :wink:

D