I had the same problem, too. I booked a pricey (for me) itinerary, got the standard "You made a reservation, but we haven't actually ticketed it yet because our I.T. sucks" email, and then...crickets. I received the "Can't do it. Call or email us" Fail when I requested my receipt in Manage Reservations. No email today, so I logged in, and was able to successfully pull up my receipt online. I hadn't thought of emailing out of the app. Good suggestion which hopefully won't be necessary in the future.
Whatever issues they experienced yesterday seem to at least be resolved via the "Manage Reservation" screen now. Who knows...maybe the OP's post brought it to their attention.