Hello,
I am trying to receive CAN data on the LAUNCHXL-F280049C but I am not able to receive all the bytes. I am only receiving bytes 4,5,6,7 which are the higher bytes. I am using PCAN-USB FD for sending the CAN data. I am also not able to access the mailbox RAM address on LAUNCHXL-F280049C. From the screenshot below, I am able to receive 99 99 00 00 data in Altair Embed. 
Waiting for your reply.