Messages only partially syncing
Since moving to a new MacBook Pro (M1 2020), messages are not syncing between my Macbook and my iPhone. Some messages appear on both devices but a number of contacts can't be messaged from my Macbook, and messages from them on my iPhone don't appear on my Mac.
I have checked that the Apple ID is the same on both devices.
I have updated to macOS Monterey but that didn't resolve the issue.
MacBook Pro 13″, macOS 10.15