UPDATE: uninstalled because the developers aren't even addressing the bug with their game. Too many games coming out to choose from these days for devs to ignore game breaking issues while some people are apparently able to play and others like myself are not. Not even a fan of the series anyway, wanted to try it out. Oh well, with any luck Fairy Tail DM will be out next week a will as other title later this January.
It has usual gacha mechanics but they give a lot of bonuses to new players like free daily summon and log in bonuses. The game does freeze once in a while but it's quick to start up again and let's you return to the battle easily.
One of the panel missions was not working so I emailed their support (in Japanese) and it was addressed and fixed not long after.