We are having this issue to since we upgraded to Wave 15 on 1st Dec. Fortunately we had a listserv upgrade in the works so am hoping that fixes it too. Our install of OWA, seems to put in the from line in a reply like this: From: listinfo [[log in to unmask]] on behalf of Daniel Nisbet Whereas the upgraded Wave 15 of Office365 looks like this: From: listinfo <[log in to unmask]> on behalf of Daniel Nisbet <[log in to unmask]> Which listserv rejects. Regards, Daniel