Originally Posted by kdgaughan
On replacement handhelds we find that it's necessary to clear the pending mail queue just before activation (e.g. before the new pin is detected by the server). I understand previously queued mail is using an encryption key from the old device and cannot be decrypted by the new device for successful delivery.
I have seen this as well. While it is not always required to delete the pending messages, it does resolve a number of activation issues for me.