I have the same exact problem. I've tried to do all the ways possible to accept the quest like via the quest menu or directly in person, but I have failed to even get an accept button.
I also have the same problem. I've recently hit level 100, but i didn't receive my reward chests. I didn't get my lvl 30 chest either. I've went to the Maple Administrator NPC in the event hall to try to accept the quest, but it gave me no option to…