Unable to delete local email in Apple Mail

I'm getting this error message when I try to delete an email in applemail. It's no longer on the server, I don't know where the original deleted email is, but I'd rather it wasn't a permanent addition to my macbook mailbox

Can anyone give me any advice on removing a local copy? Thanks

(Account name redacted) RESOLVED -email needed to be moved to another (any) folder, then delete from this new location.