facebook graph api - unreachable picture urls (403) returned by taggable_friends using Koala Rails Gem -

i using koala gem taggable_friends of logged in users of app.

when using taggable_friends via facebook api explorer picture urls of type:

https://fbcdn-profile-a.akamaihd.net/hprofile-ak-xap1/v/t1.0-1/s50x50/1511494_10101263181401141_1434607512_n.jpg?oh=c5abb8d9ba6cfba11ccd96a4e2677bc2&oe=573d99e5&gda=1462771015_c580b7037fe88c460cc4a288ef23b009

which work fine.

however, when calling taggable_friends function via code (rails version 4 koala gem) same user , same facebook app, getting exact same ids , name data, profile pics getting type of url back:

https://scontent.xx.fbcdn.net/hprofile-xaf1/v/t1.0-1/c50.50.621.621/s50x50/1004433_10200680766036422_1106849516_n.jpg?oh=8e7726bd164064d4306edf55f51810a5&oe=57334e02

these picture urls fail 403. strangely, 5% of profile pictures returned work, 95% return 403.

btw have tried both , without app secret security enabled app still these unreachable urls.

any appreciated

ok. figured out. our javascript function changing picture url downcase , links didn't work. fb picture urls case sensitive turns out.