The LinkedIn professional social network has suffered a service mysterious service outage.
The site was inaccessible from midday on Wednesday, displaying only a bad gateway error page.
At the time of publishing the Down Right Now service was reporting that LinkedIn is still likely suffering from an unspecified service disruption.
LinkedIn confirmed to V3 it is aware of the outage but declined to comment on its cause.
"We're aware that the site is currently down, and our team is working on it right now. We'll keep you posted," the spokesman told V3.
In the past LinkedIn has been targeted by hackers and cybercriminals.
In June 2012 the site suffered a massive data breach seeing around 6.5 million encrypted LinkedIn passwords posted to a Russian hacker site.
The attack was indicative of a wider interest in social networks by cyber criminals.
Numerous security vendors have said that information stored on social networks is increasingly valuable to criminals.
This is because the information can offer them key insights into the user's behaviour, making it easier for them to target them with things like phishing scams.
The European Commission recently pledged to implement a raft of new policies designed to force the services to improve their security to deal with the increased threat.