Best Buy’s website suffered a prolonged outage on Black Friday, as a concentrated spike in mobile traffic led the electronics retailer to it shut down temporarily.

The website is now working after being offline for about a hour on Black Friday morning. For a short period, a visit to the Best Buy BBY website said: “We’re sorry. is currently unavailable. Check back soon.”

Best Buy spokeswoman Amy von Walter said a spike in mobile traffic triggered issues led Best Buy to shut down the website “in order to take proactive measures to restore full performance.”

The short-term glitch comes at a critical time for the company as it aims to compete for more than $50 billion in sales that are generated for the Thanksgiving weekend. The holiday shopping season is highly competitive, especially for the Black Friday weekend when retailers like Best Buy aim to lure consumers with door buster deals. Such promotions are often popular in the consumer electronics space, where deals focus on televisions, tablets and other tech gadgets.

Online sales are important for Best Buy, with that business reporting nearly 20% growth in the U.S. for the fiscal year ended February 1. The online business is also a component of Best Buy’s fairly new ship-from-store feature–a capability that allows the retailer to fill online merchandise sales by using inventory at the company’s brick-and-mortar retail stores.

Best Buy generated nearly $11.5 billion for the nine-week holiday period last year, though domestic same-store sales slid 0.9% from the prior year as a result of aggressive promotions, supply constraints for key products and some weakness in the mobile phone market at the time.