With a Hoppie ID loaded into the EFB, I try to logon to CPDLC on the MCDU. It starts the process but just hangs and never connects. I downloaded the app from the Hoppie site (the 747 FMC) but that doesn't seem to do anything. I'm 100% sure it's user error but I can't figure out the error. Any suggestions? Thanks!

You can't really logon to a CPDLC station unless the other station is active and accepting your logon request. If you just want to verify that your Hoppie ID is setup properly you can check the messages archive on the Hoppie website.

And after update ypu need to set hoppie id again...