They posted something in the official discord server.

Hello @everyone! Unfortunately due to a Bug/Glitch with the Missions General Mobilization event, it has been temporarily disabled. We deeply apologise for this situation and know how frustrating it can be and will try to do our best by you all. Edit: If you still have MGM Gift Boxes in your inventory, it is recommended to not open them until we have more information or late Wednesday this week! Thank you for your patience with us during this time. Best Regards, Naruto Online Support Team

i'm sure they will compensate it nicely with like 3 purification scrolls, 2 medium refine runes and a potato