[Help needed] Hue Ceiling light takes 5 sec to come one and blinking

Purchased Hue ceiling light (Devote hue). Installed it on my staircase with standard light switch on top floor and dimmer below (standard dimmer, not philips) and bridge. Whenever i press light on it takes about 5-7 seconds, then it flickers in green colour and then it comes on. Any ideas how to fix it? thank you in advance