If you can’t share Mac computer screens

If you’re having problems sharing your screen with another Mac, or viewing a shared screen on your Mac, there are several things to check.

Make sure you turned on screen sharing or remote management and set up sharing permissions on the Mac whose screen you want to share. See Turn Mac screen sharing on or off.
To check the sharing permissions on the other Mac, choose Apple menu > System Settings, click General in the sidebar, then click Sharing. Click next to Screen Sharing, then make sure you’re in the list of users who have permission to share its screen.
Open Sharing settings for me
Make sure neither Mac is in sleep. If necessary, adjust the sleep settings for each Mac.
Make sure both computers are connected to the same network.
To check your connection, choose Apple menu > System Settings, then click Network in the sidebar. The indicator next to your type of network connection should be green. For a Wi-Fi connection, click Wi-Fi to check the network name.
Open Network settings for me

Helpful?

Mac User Guide