This error occurs when Screens attempts to establish a connection to the remote computer, but it doesn't receive a response from that computer. This can occur for a couple of reasons.
- The router's public port is closed/filtered. Check your router's firewall/security/NAT settings to make sure the port is open so that Screens can communicate through the router with the computer you're connecting to.
- Your ISP uses Carrier-Grade NAT/Large-Scale NAT.