Simple rules tho:

"A team member had put an insufficient quantity of fuel into the car, thereby resulting in the car having to be stopped on the circuit in order to be able to provide the required amount for sampling purposes,” explained the FIA in a statement. “As the amount of fuel put into the car is under the complete control of the competitor, the stewards cannot accept this as a case of force majeure.

"The Stewards determine that this is a breach of Article 6.6.2 of the FIA Formula One Technical Regulations and the Competitor is accordingly excluded from the results of the Qualifying Session. The Competitor is however allowed to start the race from the back of the grid."