Messages are not syncing to all devices
I have an iphone 16 pro max, 2024 imac, and new macbook air. (iphone and imac sync together). i cannot get messages to sync to the macbook air. however, messages can be seen on macbook air. if i delete a message on iphone, it will delete on imac but not on macbook air. i am signed into the same apple icloud account on all devices. both macs running latest version of sequoia. help!
MacBook Air, macOS 15.3