Master Series Chest Doesn't Pop Up

I also have this problem too. I'm on trench master event on stage 2 and can't claim the chest. I've tried restarting my device, unistall and redownload the app, force stopping the app. I even tried downloading the app on another phone to see if it would help, but it still won't work. I also have another chest on the training camp events that won't load either. Please help.