[Bug] Official Notice About The Daily 8 or 80 Magic Stone Gacha
Sources Notice
In short: If your box is full, you may not be able to open the 8 or 80 Magic Stone gacha mail.
The official notice tells you to please create space by fusing, selling etc. before trying to pull. This will be fixed in a future update.
I guess they never thought about a Magic Stone gacha initially…