My wife and I just purchase iPhone 5s. We both have the same problem…can’t delete messages from our Trash Mailboxes. When attempting to do so the following message appears:
“Unable to Move Messages
The message could not be moved to the mailbox Trash”
The local Verizon Store Manager had never seen this before and theorized it might be related to a setting at my ISP, where they host my domain name. Doesn’t make sense to me as the messages in my Trash mailbox have obviously been downloaded on my iPhone. But, hey, I’m open to any/all suggestions.
Assuming a IMAP email connection… this is all just a guess but:
It sounds like what’s happening is that the “Trash” folder provided by your ISP is “fake” (“fake” meaning, it’s just a normal folder that happens to be named “Trash”.)
What the iPhone is doing is trying to remove the item from that folder to the actual IMAP trash folder, and failing. That’s why your iPhone looks like it’s trying to move an item already in the trash to the trash.
I’d do what the guy at the Verizon store recommends and talk to your ISP.
I used to have that problem. IIRC, the fix is:
On the iPhone, open Settings-> Mail, Contacts, Calendars
Select the mail account in question
Select account again
scroll down & select Advanced
Under 'Mailbox Behaviors" set the Deleted Mailbox to be on the phone, not the server.