The tech found in Tesla’s vehicles is among the most advanced in the industry, but sometimes it’s a bit too complicated for its own good. Case in point, the ability to unlock the car with your phone, which, when it crashed, left some Tesla owners stranded outside their vehicles.

The cars’ primary method of being locked and unlocked is with a keycard (or key fob), but owners also have the option to perform those functions via the Tesla app and a Bluetooth connection. However, if you were to only bring your phone with you when the app crashed, you wouldn’t be able to get into your car – and that’s exactly what happened this past Friday to around 500 Tesla owners.

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One Twitter user wrote: “I’m experiencing 500 server error to connect my @tesla Model 3 on my iOS app in Seoul, S.Korea. Seems like this is a worldwide issue. @elonmusk.” In response, Musk said: “Should be coming back online now. Looks like we may have accidentally increased verbosity of network traffic. Apologies, we will take measures to ensure this doesn’t happen again.”

The incident was first reported by Electrek, who subsequently provided updates as the story developed. And according to Reuters, Downdetector reported the main 500-user outage to be at around 4:40 PM EST, with another outage report of 60 users at around 9:20 PM that same night. Since then, the issue has been resolved, but hopefully it will serve as a lesson to not rely only on a smartphone – just in case.

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The fix didn’t stop Ford’s North America Product Communications Manager and active Tesla critic on Twitter from taking another shot at the Californian EV Brand.