Per a discussion with @dpgeorge CAN is not currently supported on H7 MCU.

I am hoping to see CAN support on the H7 device, and eventually CAN-FD support. I think FD (Flexible Data-Rate) is still new enough that the need for full support is definitely not a requirement, basic support of 11bit and 29bit CAN would be more than enough to allow the H7 to replace the F7 in most use-cases.

Unfortunately my time and skill on this is limited, and willing to provide financial support if needed, but this a gating item for me to switch over to the H7 and I image other might want/need this as well.