Well somehow things just keeping getting more annoying, but here are the gotchas if you have your own generic IMAP account:
- MacOS seems to get confused about the default account. And you get this strange,
cannot move message to (null)message. What this means is that you need to go to Mail/Preferences/Accounts and look into your account and then in the Mailbox Behaviors and click on Drafts, Sent and Junk and Trash and select the server side folders typically INBOX/
- iOS has the same issue, the defaults are not set, so after you sign on you need to go to the Settings/MailAccounts/ and pick the new IMAP account/Advanced and set all the Mailbox behaviors to use the server side.