Allow Screen Recording
Open System Settings → Privacy & Security → Screen Recording. On newer macOS versions the section may be called Screen & System Audio Recording. Allow RemoteDuo, then follow any restart prompt. Without this access, a connection can exist while the screen remains unavailable.
Allow Accessibility for input
Open System Settings → Privacy & Security → Accessibility and enable RemoteDuo. This lets the host apply authorized mouse and keyboard input. If you can see the screen but cannot type or click, check this permission and whether your session has control rather than view-only access.
Check Local Network access
On macOS 15 or later, review System Settings → Privacy & Security → Local Network if nearby devices cannot establish a direct connection. If RemoteDuo appears, check its setting. A missing prompt or list entry does not by itself identify the cause of a failed connection.
Reopen and check the installed app
After changing permissions, reopen RemoteDuo. Following an update, confirm you are opening the intended copy in Applications rather than another extracted build. Development signing can affect how macOS recognizes permission grants across builds. Avoid deleting system privacy databases or disabling macOS security to troubleshoot.