That looks like you need to stake more WAX tokens to CPU. If you are new to wax and haven't staked any tokens, or if you've done a lot of transactions on wax that exceed your CPU power, this could be why. If you've done a lot of transactions in the past 24 hours, typically all you have to do is wait a little bit (sometimes longer, sometimes shorter) to recharge your CPU usage.
RE: Blockchain RPG - How To Equip Items (with Giveaway!)