keep pressing OK, then wait for the launcher to close (or u can force close), then re-open launcher.
rinse n repeat.
eventually there will be another different popup says "there is a new update", then press Yes.
or, u can go in dragonica folder, go into release folder, find dragonica.exe. that will straight enter the game. (but if ur client is outdated, will get message "Wrong Version".
happens to me many times especially if got update. but now i long time no play d. hooked with other server.