US President Donald Trump’s Twitter account briefly vanished on Thursday but has since been restored, the social media company said.
An employee deactivated the @realdonaldtrump account, it said, clarifying that it had been their last day in the job.
The account was down for 11 minutes and Twitter is now investigating.
The president brushed off the outage in a new tweet on Friday, suggesting it showed the impact he was having.
Tweets from Mr Trump, who has 41.7 million followers, have frequently caused controversy.
The latest incident has sparked debate about the security of the president’s account, given the potential consequences of posts falsely attributed to Mr Trump being published.
However, @POTUS, the official account of the US president, was unaffected.
On Thursday evening, visitors to Mr Trump’s page for a short time could only see a message that read “Sorry, that page doesn’t exist!”
After the account was restored, Mr Trump’s first tweet was about the Republican Party’s tax cuts plan.
Twitter said it was investigating the problem and taking steps to avoid it happening again.
It later said: “Through our investigation we have learned that this was done by a Twitter customer support employee who did this on the employee’s last day. We are conducting a full internal review.”