Tesla chief executive Elon Musk has acknowledged that the automaker “dropped the ball” with the launch of the facelifted Model X.

Tesla shut down the production line for the Model X at its Fremont factory in December 2020 to prepare for the launch of the facelifted variant. It wasn’t until October 2021 that the first updated Model Xs reached the hands of customers and even now, it is only customers in the U.S. that are receiving new Model Xs.

Prompted by a comment on Twitter suggesting that many Tesla fans are unable to criticize the car manufacturer, a Tesla investor stated that “the refreshed Model X rollout has been horrible & the lack of communication to customers who have been waiting for a year or more for their car & keep receiving delays is disappointing.”

Watch Also: Surprise, Surprise, Tesla’s Full Self-Driving Beta Causes Accident

Elon Musk quickly responded and stated that the Model X is a very difficult vehicle to build.

“We dropped the ball badly regarding new Model X production ramp & still haven’t fully recovered,” Musk wrote. “Was idiotic to stop production of old X in Dec 2020 when there was still plenty of demand! Model X is an extremely difficult car to build. Most complex passenger car ever. Limiting factor is interior trim.”

The refreshed Model X was first announced by Tesla in January 2021 alongside the updated Model S. It features tweaked front and rear fascias but the most significant updates have been made in the interior with a new yoke-style steering wheel, an all-new infotainment screen, and a 22-speaker audio system. The launch of the Model X also brought with it a flagship Plaid variant that sports three electric motors, delivers 1,020 hp, and allows the SUV to hit 60 mph in 2.5 seconds, sprint down the quarter-mile in 9.9 seconds, and continue through to a 163 mph (262 km/h) top speed.