AirPods 2 Wirless charging not working

I have buy AirPods 2 with Wirless charging case but not charging ( i have use “ Belkin Boost Up Qi (5 W) Wireless Charger “ this Wirless charger work my iPhone Xs perfectly) but i have use AirPods 2 starting all ok but after few min Belkin charger green light change to red and continue blinking and i have check others Qi charger but same i think AirPods 2 charging case not perfect i have buy Wirless power bank i have use my iPhone Xs charging is ok but i have use AirPods 2 no charging i have Reset many time AirPods 2 but same problem