I'm using my S6 edge with a hosted Exchange account and the default Samsung e-mail app. I have a number of e-mails (currently, 14) in my in-box that will not be deleted on my phone. If I delete them on the phone, they reappear there later! The same messages do not appear anywhere else when I access my Exchange account (Outlook, iPad, etc.) So, it is definitely something specific to the phone's e-mail app. (I've used three previous Samsung phones without this issue.) Is anyone else having this problem, and what to do about it?