If an increased payload capacity was required, six boosters were flown instead of three, in a configuration known as the Delta N6, or "Super Six".
In addition, the leaking LOX started pushing the stage off its proper flight path.
The guidance system tried to compensate by repeatedly firing the attitude control jets, but this resulted in the rapid exhaustion of their propellant and the launch vehicle started tumbling uncontrollably.
The ITOS satellite separated on schedule, but was facing in the wrong direction for orbital insertion, so it simply reentered the atmosphere and burned up.
The second stage itself and several pieces of debris did manage to reach orbit and remained there for several weeks.