Some Tesla owners on Wednesday reported they had trouble getting into their cars, checking how much the battery had charged and accessing other services, a symptom of increasingly connected cars and how they are at the mercy of fragile Internet connections.
The cause was a network outage rippling across automaker Tesla’s range of services, hindering users’ connections to the company’s mobile app and website. It was an unusual occurrence for Tesla, though it’s not exceptionally rare for an Internet-connected service to see brief outages from time to time.
That's why Tesla issues physical key cards to unlock cars as a backup.