WASHINGTON: Tesla CEO Elon Musk reported late Friday that an app problem that was keeping a number of drivers worldwide from using their cars was on the mend after a server issue was resolved.

Multiple Tesla drivers tweeted that they were no longer able to start their cars with their phone apps and had to use keycards if they were lucky enough to be carrying theirs with them.

Musk responded directly to a South Korean driver who reported receiving a message about a server error while attempting to connect with his Tesla Model 3 via the app on his iPhone.

Functionality should "be coming back online now. Looks like we may have accidentally increased verbosity of network traffic," Musk tweeted.

"Apologies, we will take measures to ensure this doesn't happen again," he said.

But drivers had already posted a multitude of complaints online, such as one who tweeted: "im stuck an hour away from home because i normally use my phone to start car."

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Another lamented that "THOUSANDS of @Tesla owners are locked out of their vehicles because Tesla servers went down over two hours ago."

"I'm one of them. They said we'd be helping the environment by owning an electric vehicle, but 'Walking' isn't what I had in mind."

The problem seemed widespread with tweets surfacing in countries such as the United States, Canada, Denmark and Germany.