Originally Posted by gibson_hg
It's also worth checking that the user did not configure a BIS account for this device.
Only one mailbox per device will work. Odds are it's a BIS account, that's the most logical solution anyways.
Pretty much where I was going with it as well.
Open up 1 message each for both addresses on the BB.
At the top, check the received using: field. One will definitely say Desktop or Desktop Secure, but check what the other one says.
Most likely Unknown, or a bis integrated email address.
Let us know.