This happens frequently in one of the 4 accounts I have on desktop. It's the one I use most for business and it is very frustrating to have emails delayed while I have to go to the web based yahoo and try to pull up the message I want sent and do it again. I've done all the "fixes" that I can find by googling for answers and in the forum and nothing works. It doesn't happen in my other two yahoo accounts. Is it because this one is the primary? I'm really sick of it.