I have the same problem, worked fine for months then suddenly no attachments just the email stating here is your attachment.
I've tried re-booting printer, shutting wireless off and on again, emailing to different accounts from different providers, scanning as image and document all the same result.
HP, I think your back-end servers are down maybe? - they're not processing the documents into attachments?
I've seen 3 similar questions on these support boards and no responses form you yet which is a shame...