why application is blocked for me and other don't ?

[ziko2016]

Open dns it worked on my laptop and my phone correctly.But other devices the applications for example instagram app it blocked for me but in other devices who use my wifi are still worked with them the app.
for the first time I thought that Open dns don't affect to other devices then I take one of devices and I use chrome and searching (www.instagram.com) and it blocked by open dns.
So I'm confused that's why I remove web content filtring and set none 

then I add domains of instagram  (always blocked) it blocked for me but in other devices doesn't work.

[reham1]

Please add the following domains to your (whitelist) Always Allow list and see if this resolves the problem:

instagram.com
api.instagram.com
cdninstagram.com

These domains usually will block Instagram but if you are still having problems please add these domains as well:

connect.facebook.net
staticxx.facebook.com