NEW YORK (AP) — Twitter users were unable to access the micro-blogging service for part of Thursday.
Twitter initially said on its status blog that its engineers were investigating access problems to the site. It then said it resolved the issue. Apparently that wasn't the case, though, because about three hours later, Twitter removed the "resolved" part and said that the "issue is on-going and engineers are working to resolve it."
Twitter was working for many users by early afternoon, but as of 4 p.m. Eastern the company said the issue was still ongoing. It did not say how many users were affected by the outage, or how long it lasted.
Outages were once common on Twitter, but that was several years ago when it was new and trying to manage growth. It was shut down at least twice in August 2009, once for several hours, when hackers hobbled the site by flooding it with fake traffic in a "denial of service" attack.
There was no indication Thursday that the outage was the result of malicious attacks. Rather, Twitter said it was a "cascaded bug," a software error that seeps into various parts of the system instead of being confined to a particular area.