Unable to move message to Trash

This definitely works. Nice job all

I fixed this by changing the Trash selection under Advanced Settings* to "On The Server" instead of "On My iPhone"

* Settings>Mail, Contacts, Calendars>Your Email Account>Account>Advanced>Deleted Mailbox>

On iOS 8.x, you may need to specify which folder on the Exchange server is used for deleted items. This fix also works for IMAP Servers:

Settings App > Mail, Contacts, Calendars > [Account Name] > Account > Advanced > Deleted Mailbox. The last window lets you specify which folder on the mail server is used as the trash folder.

I Just found that for me it happens when it is 'All mailboxes' that is selected. For individual boxes moving to trash works fine because it knows which trash account to use.

Thanks. This worked

Thank you so much! This did it for me on my iPhone 6.

THIS is the one that works. Very easy.

Thanks so so much for posting this. Worked like a charm. 🙂

A note to those still having a similar problem and for whom the solution of resetting accounts did not work (as it did not for me).

I had this problem with a particular email account on all my devices, once of which had iOS7 and another iOS8. Couldn't delete messages as described in the original question. The problem turned out to be that the Apple mail tries to move the deleted messages to the local Trash folder by default, and my IMAP email account didn't like that. So I changed the settings to move deleted messages to a Trash folder on the server, and that fixed the problem.

To change the settings, go to "Settings" on your device, then click "Mail, Contacts, Calendar", select, the problematic mail account, click on it, then click on the name of the account again until you get to the screen "Account", which shows all the server settings. Scroll down, click on "Advanced". Once there, click on "Deleted Mailbox" and select a destination folder on the server (e.g., Trash), and NOT the Trash folder on your device.

Thanks for this explanation ! It wouldn't let me delete the Trash but I emptied the Trash and the Junk folders and problem solved ! It's 2015 and this fix pertains to my iPhone 5c using the latest IOS.

GGreat answer, this sorted out my issue with junk messages on ipad. Thank you

This method helped me as well, finally!

Thank you so much for this practical solution to a nagging issue!

Thank you so much for this simple solution to a most aggravating issue!

I tried the delete account, switch off, wait, then reload the account - that seemed to work, and I also typed 'inbox' in the IMAP, so hopefully all's now well...!!!