DETROIT — Tesla apparently is having trouble informing customers about deliveries of the Model 3 mass-market electric car.

In a Twitter response to a customer Wednesday, CEO Elon Musk wrote that some “may experience longer response times” because of a large increase in vehicle deliveries in North America. He wrote that resolving the issue is Tesla’s top priority.

Earlier in the day, the customer tweeted to Musk that he couldn’t get a vehicle identification number from his sales adviser even though he is scheduled to pick up his Model 3 on Monday. The customer wrote that it was frustrating and his loan for the car is up in the air.

Musk apologized and wrote that he’s working on the issue. Tesla spokesmen did not immediately comment.

Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.