999 error or automatic sign out in Yahoo! Messenger for Mobile
This article discusses an issue where customers may receive a '999' error or get automatically signed out from the mobile version of Yahoo! Messenger.
999 errors are often caused by unusually high activity between a computer or device and a specific page or pages on the Yahoo! network.
Try waiting several minutes before using Yahoo! Messenger again. If the issue continues, please try the resolutions suggested in our article, Problems accessing Yahoo! Mobile webpages.