The projector is overheating and needs to be cleaned. A common cause of projector shutdown is overheating, which can be triggered by dust accumulation, blocked vents, or faulty fans. The projector has a thermal protection circuit that turns it off when the temperature reaches a certain level, and it will not turn back on until it cools down. To prevent this issue, the projector needs to be cleaned regularly and placed in a well- ventilated area. The video cable, the bulb, and the outlet are not likely to cause the projector to turn off intermittently. Reference: [CompTIA A+ Core 1 (220-1101) Certification Study Guide], page 18.