probably cause you didn't claim a day.

Hello!

I think, you forgot to claim one of the milestone rewards, I suggest you to check each milestone rewards and see if you miss something out. But if everything is claimed already, then it must be something else and recommend you to visit our Bugs and Support Section and report it or go directly to our Customer Support Service by here clicking the "?" *on at the top-right corner of your screen when you log-in in the game. Thank you.