https://bugs.kde.org/show_bug.cgi?id=420883 --- Comment #1 from Justin <jgraham at mailbox.org> --- SOLVED: I manually deleted all .config and .local files relating to Kmail and Akonadi, uninstalled Kmail and Akonadi then reinstalled both. Mail now sends! -- You are receiving this mail because: You are the assignee for the bug.