bara qubbeia , According to the list, link #1 below the phone should connect to galaxy S6 , maybe factory reset and follow instructions in link #2 or link #3. Still no go, return watch under warranty for replacement/refund. Good luck.
I hope this helped you out, if so let me know by pressing the helpful button.
http://www.samsung.com/hk_en/mobile_compatible_list/
http://techlife.samsung.com/pairing-galaxy-gear-galaxy-smartphone-1345.html
http://samsungrumors.net/use-gear-s-android-phone-apple-iphone/