We have had our Mac Yosemite since Christmas, switching from Windows PC and I use two email accounts, ntlworld and yahoo. Inexplicably, the yahoo account has suddenly started labelling all my sent messages as junk. I cannot find a way to solve this. Most help subjects deal with incoming junk. It doesn't happen with the ntlworld email. I keep ticking "not junk" but it doesn't change things. I would welcome suggestions.
iMac with Retina 5K display, iOS 8.3
