Hello, commanders!
This is Tia, the GM of 'Light of the Stars.'

Currently, we are experiencing an error related to the use of Blackstone Crystals. When you use up free Blackstone Crystals, the screen shows 0 Blackstone Crystal even though your paid Blackstone Crystals should remain. When this happens, it does not allow you to use the paid Blackstone Crystals.

We have confirmed that if you acquire at least 1 free Blackstone Crystal, the total number of Crystals you own restores, allowing you to use your free/paid Blackstone Crystals without any problem.

We have found the cause of this error. It will be fixed in the next maintenance period.

We apologize for your inconvenience.

Thank you.