From https://stakecube.info/important-announcement/

I regret to inform you that StakeCube will be temporarily halting deposits, trading, and withdrawals with immediate effect. 

The exchanges go down, so always sad to hear about another site having severe problems. There is a small glimmer of hope:

However, my first priority is to talk to some of the core team members now, so they can take over control.

As always, there is the huge trade off. If you are responsible, manage your own coins in your own wallets. But the risks of using a third party get highlighted regularly.