I use Rackspace, paid account. I’ve whitelisted the email address in the client, and the emails are coming through, just on a delay of about an hour, by which time the login session has ended on the mobile web app.
From the headers it’s clear that they are being sent on time and delivered an hour later. I can’t tell if that’s an outbound issue or if Rackspace is somehow holding the emails before delivery. This has never been an issue before today, I’ve used the system successfully for a month or two.