I can’t either. I have written a similar app, and when the user is offline, the app spools the work they do into on-device storage. When the user comes back online, the spooled work is uploaded to the server. It is at that point where you could theoretically require another login before the server will accept the spooled work, but there isn’t any way to prevent the user from doing offline stuff offline, because the user totally controls that environment.