Having the same problem. Set up a forwarding email exactly as described here a couple of weeks ago and thought it was genius.

It's set up as follows:

my personal email (not associated with a QB User account)  > send to > ReceiptsForwardingEmail @gmail.com  > is set up to auto-forward to > QBO receipts email

It WAS working for a week or so, now isn't. 

Instead I get a reply from Intuit, sent to my original Personal email to say I'm not set up to send receipts.

No, I know, hence the forwarding set-up as described.