Because you timed out of this game:
Timing out of a tournament game automatically results in disqualification by the OGS tournament system. But, since it happens automatically and doesn’t finish your other games, it may be that you’re not actually disqualified as far as the Kuksu tournament is concerned (only as far as the automatic system is concerned). According to the forum topic about the tournament you are probably fine to progress to the next round, but you’d have to ask @gamesorry.