UPnP, NAT-PMP, or port mapping is disabled or unavailable on the router
First, confirm that your router supports UPnP (also called NAT-PMP or simply port mapping). Refer to your hardware documentation to learn how to activate this feature. If UPnP is not available on your router, you must perform a manual configuration.
If you have more than one router on the same network, confirm that one of them is set to Bridge Modeand that all of them support UPnP. (Note that some modems also act as routers.)
Some manufacturers claim that their hardware is UPnP or NAT-PMP compatible, but some routers use incorrect UPnP implementations. If you seem to have problems with the automatic configuration of your router, you must perform a manual configuration (Mac) or use another service (PC).
Screens Connect displays a "port mapping failed" error
If this error occurs suddenly after a successful connection history, try restarting the router and the remote computer.
If the problem persists on your Mac, you must perform a manual configuration (Mac). If you have installed Screens Connect on Windows, you will need to use another service (PC) to make your PC accessible remotely.
Wireless access point (hotspot)
If you use Screens Connect on a computer that accesses the Internet through a wireless access point (for example, an iPhone with Personal Hotspot enabled), Screens Connect will not be able to automatically map a port and display this error.
If your Mac or PC is connected to a public network (eg school, library, café, etc.), Screens Connect may not be able to automatically map a port and display this error. If possible, contact the network manager to see if you can enable UPnP or perform manual configuration (Mac) or use another service (PC) to make your computer accessible remotely.