User blog comment:Dragonjet/KC3改/@comment-202.67.42.36-20150523164444/@comment-1820055-20150523234324

must be your internet, check if you can play via direct DMM website without the kc3 frames or API link.

my guess is that the response header content-length does not match the actual length of the response body which means it was cut-off in the middle of transfer.