If I understand correctly, you are setting up the system from scratch? The system has never been used?
First thing I would do is run "set-defaults" at the LOADER prompt, then boot to maintenance mode, and then run "ha-config show" to verify both nodes show as "mccip". Once that is confirmed, boot again and choose option 9a, then let the system reinitialise and start from that point.
Ok, unfortunately I think it will be necessary to open a case with our support team, it sounds like you've done everything right (especially since you mention you have several other successful installs complete)
Best regards and you are welcome to send me the case number or post the number here, as I am interested in the root cause.