Red Eléctrica, Spain’s electricity grid operator, ruled out a cyberattack, human error or unusual weather. Experts say it could take weeks to determine the cause.

Officials for the Madrid Open cancelled Monday's play amid a blackout in Spain that impacted the tournament's facilities. The blackout caused a number of logistical problems at Caja Mágica with the scoreboards going dark and the loss of lighting to help fans navigate the venue:

Electricity is pulsing through Spain and Portugal again after a massive outage knocked out power in both countries on Monday. So too are questions.