Doesn't Power on anymore, no idea why

EAN: 0013803136692
Compatible Brand: Canon
Brand: Canon
Type: Shoe Mount
Mount Interface: Intelligent Accessory Shoe
Model: 600EX-RT
Light Type: LED
MPN: 5296B002
Features: Swivel, Zoom, AF Assist Light
Guide Number: 60m/Iso 100
To Fit: Digital Camera