Message too large which server has rejected how do I delete it

I have a message which is too large for the mail service which em client keeps trying to send … and ultimately it fails. The message is not visible at all in EM client, but keeps reappearing as a synchronisation failure. How do I delete it?

Right-click on Smart Folders, and choose Outbox, then look in the Smart Folder Outbox.

Yes I can see the outbox, but the message is not visible there either.    Hence my rather puzzled request.

As is common with desktop email clients, the Local Folders Outbox is used to store messages as they are being uploaded to the server. Showing the Smart Folder Outbox will include messages in the Local Folders Outbox. If the message is not in that Outbox, (not the account Outbox) then it is not on your computer.

Saw another post and found your explanation as to how to delete.     I had not enabled the visibility of smart folders so your original post did not make sense.     Once i enabled smart folders and deleted the emails in the smart folder outbox, then all was resolved.       Thanks a lot