Why The game keep crashing?!?!?

Ok so I tried finishing my mission right? And I pressed it and it said that it was taken already, so I clicked it and it said "youve accepted the request" but then when I arrived it said that there was an unknown error then I pressed "ok" then it went back to the title. I tried to finish my mission 7 times, I even download the game again and it still wouldnt let me continue my mission. So can yall plz do something about that? I really want to finish my mission, the game is addicting

DayjahBuie about MMORPG Stellacept Online