Title says it all, the mystery legendary chest you receive for 62 points in the Event center does nothing when used. Fortunately it doesn’t disappear either, so it should be possible to fix.
Mine did the same thing!
Also same problem. Trash Game
You didn’t supply details of whether you’re on PC / Android / iPhone.
I play on PC and the chest opened fine for me.
Indeed, I usually don’t do that when it happens on all platforms.
After a few days it opened for me as well, either a stealth fix or it was locked until a certain date for some reason.