NEW YORK (CNNMoney) – It’s a retailer’s worst nightmare on Black Friday: its website goes down.

That happened to Lowe’s website Friday morning. The home improvement retailer’s site experienced a temporary outage, and it attributed the error to “maintenance.”

Customers trying to shop Black Friday deals on the site took to Twitter to complain.

“@Lowes My cart was full and now the website is down!” wrote one Twitter user.

The retailer wrote back: “We apologize our web site is down for maintenance. It will be available soon.”

Some customers trying to shop on Lowe’s website saw a message that read: “The site is currently offline and will be available within the next hour.”

The website appeared to be back up and running as of 11 a.m. ET.

Lowe’s did not immediately respond to a request for comment.

“When sites go down, it’s quite disastrous,” said Sucharita Mulpuru, a retail analyst at research firm Forrester.

“But it nonetheless happens every year, though is it less common than 10 years ago … Retailers try their best to avoid problems like this but the unexpected can happen,” she said.

In 2015, Target’s website experienced outages on Cyber Monday. Last year, Macy’s website crashed on Black Friday.WHAT OTHERS ARE CLICKING ON: