Tesla sales plunged by more than half last month in several European countries in a sign that Elon Musk could struggle to revive the company after he shifts from his Washington cost-cutting work to day-to-day operations again.

Douglas McIntyre, Editor-in-Chief at Climate Crisis 24/7, reports that Elon Musk is officially returning as Tesla CEO after a four-month hiatus during which he advised the U.S. government. Rumors suggest Tesla’s sales and brand image declined during his absence,

According to the Wall Street Journal, members of Tesla’s executive board recently explored the idea of replacing Elon Musk, a revelation that sparked the billionaire’s outrage. The report claims several executive search firms were contacted last month to identify a potential successor to Musk as CEO of the electric vehicle company.