The Mac appears offline
Check the host first: awake, logged in, RemoteDuo running, incoming access enabled and an active internet connection. A sleeping Mac, a quit app or a network outage cannot be fixed by retrying from the controller. FileVault unlock and pre-login access are outside the current beta.
Sign-in or credentials fail
Use your email and member password for account sign-in. Use the host’s six-digit device ID and PC password for the remote connection. Check any temporary lockout message rather than repeating attempts. Follow any access-limit message in the app and use matching current desktop builds.
Connected, but no screen or input
A blank or unavailable screen calls for checking Screen Recording permission. A visible screen with no typing or clicking calls for checking Accessibility and your control permission. These are different from a direct-network connection failure. Open the permission guide.
Online, but direct connection times out
Routers translate local addresses to public ones using NAT. Some networks create different external mappings for different destinations, or place devices behind several routers or carrier-grade NAT. Firewalls can also filter traffic or isolate guests. The devices may find each other through signaling while still having no usable direct route.
Desktop builds can try an additional direct TCP path where compatible router mapping is available. This is another direct attempt, not a relay or a guarantee. A router-mapping timeout does not prove that the router lacks support, and a connection timeout alone does not prove which firewall or NAT caused it.
Compare networks and use diagnostics
Test the same pair of devices on one local network, then on the intended external network. If allowed by the network owner, compare with another trusted network. Do not disable firewalls or open permanent router ports simply to make the warning disappear. Follow the administrator’s policy on company networks.
The app can attempt recovery after some interruptions and display connection diagnostics. Keep the exact stage and error from both devices for the same attempt. Automatic reconnect cannot create a route that the network does not permit. RemoteDuo does not provide relay fallback.