Hi Mike 
Do you have any errors in the javascript console? Does the preview work in safe mode?
It should definitely show something:
As for editing digests’ content, I believe it’s not possible yet.
Hi again Mark,
It appears that the preview will show nothing if there’s no new content to be displayed. It may be the cause.
Try changing the date to an older one
Does new content have to be at the Topic level, or will new replies not be considered new content?
I believe it includes new topics rather than replies to existing ones.
In my use case, most of the time users reply to existing posts, and there are rarely new posts. Is there any way to treat replies as new content in this case?
I think it does include a ‘popular posts’ section as well actually, though clearly my test users have not been generating enough popular posts recently to be included. I shall have words with them.
You can adjust the amount included using digest posts. There’s also the user preference of whether to include TL0/newuser content in the Summary as well, which may throw your tests off?
Hi,
I set “Digest topics” and “digest posts” to the minimum value(1) and still did not generate digest emails.
I would like to confirm if you will support generating digests for replies instead of creating topics in the end?
I have the same issue, did you manage to solve it?