Ah! I misread your issue then.
Yeah, I think you missed or misread this bit:
But the odd thing is that in the App Email settings on the old server it has always been and is still ghost.app
I can only guess that it was working there because I had set-up the required email addresses that are set in the portal settings in Ghost:
I guess when Cloudron couldn't find that mailbox on the new server it tried to just send as 'ghost.app' instead? 🤷
But yeah, as you say, would be good to somehow remind users this might need to be done too, like you say:
Mmmm... I wonder how the user can be reminded of this. I think for a start having this in the doc page as a checklist (which is what this thread is about!) will help.
But maybe whenever importing an app a pop-up could appear saying something like "you might also need to recreate mailboxes on this domain" or something? 🤷