keyword blocking of instagram.com does not work

i can block a number of sites with the keyword blocking, but for some reason i'm not able to block instagram.com had the same issue with my N300 router as well. everything but instagram.com would get blocked.

Any idea's?

Guess modifying the hosts file to block instagram.com is next up. but i wanted it to be router wide so it could be blocked from other devices, not just the one pc.