Rated 5 out of 5 stars

Same problem with 1.0.0.10. Will not login, but will open Yahoo mail when you double click on the icon. Was working great before, so will rate as if it was 1.0.0.09. Returned to 1.0.0.09 and all is well/

This review is for a previous version of the add-on (1.0.0.10). 

So far everyone who has told me that 1.0.0.10 doesn't log in, had it start working by itself when I asked them for debugging data.

If you still can't log in, follow the steps at http://ymnotifier.mozdev.org/bugs.html and send me the debug data so I can figure out why.