Spam folders are grayed out and unavailable for transferring junk mail
Spam folders are grayed out and unavailable to transfer email from my inbox on my iPad and iPhone. Why can't I move junk mail from my inbox to the spam folder so my spam filter learns what is spam? I have to go to my Mac computer to make a transfer.
MacBook Pro, OS X Yosemite (10.10.3), iPhoto 9.6.1 (910.42