Yahoo Mail team recently found that some versions of Skype plug-in for Firefox causing Yahoo mail to load slowly on Firefox and sometimes Yahoo mail throwing this error message,
YDOD error 999
Skype team worked with Yahoo and Now yahoo has fixed this problem in latest version of Skype and recommending Yahoo mail users to upgrade their Skype Firefox plug-in to Skype 4.1. You can download version 4.1 from Skype. After you upgrade, check in Firefox to ensure you have the latest version – 3.3.0.3971 – of the Skype plugin. (In Firefox, just click ‘Tools’ then ‘Add-ons’. In the window that opens, find Skype and check the version number.)
