Many users had difficulty accessing Twitter.com on the Web and Twitter's third-party mobile applications early Thursday, ABC News reported.
The service disruption also hit Twitter's new video sharing service Vine.
"Some users may be experiencing issues accessing Twitter. Our engineers are currently working to resolve the issue," Twitter posted on its status blog at 10:25 a.m. EST.
Twitter suffered a similar outage on Inauguration Day earlier this month and posed the same status statement on its blog Jan. 21.
Although it has significantly upgraded its server capacity in the past two years, Twitter has been infamous for its outage problems and the appearance of the "fail whale" page being seen by many users today.