I can't modify receiving IMAP accounts. I have 2 IMAP accounts, and when I click under Settings -> Configure KMail -> Accounts -> Receiving the Modify-button, the window does not open. Instead the working account gets invalid. The message is "Unable to start".
I found the issue, when I configured a new user for Wayland, which is now working fine. But the issue is to be found also in my old Plasma user.
Version is kmail 17.04.1-1.