What was belshazzar found wanting?

Belshazzar, the Babylonian king, was found wanting due to his hubris and sacrilege during a banquet where he used sacred vessels from the Jerusalem temple to drink wine. This act of defiance against God was symbolized by the mysterious writing on the wall, interpreted by the prophet Daniel as a divine message indicating that Belshazzar's reign was weighed and found insufficient. Consequently, he was judged for his arrogance and failure to acknowledge God's sovereignty, leading to his downfall that very night.