Guest networks often restrict communication between devices while still permitting internet access. A phone and television can both browse online yet fail to discover each other. Local isolation is a different problem from a slow media connection.
Check which network each device uses
Compare the actual network name and router assignment, not just the presence of a Wi-Fi icon. Some systems apply isolation even when names look similar. Casting discovery typically needs suitable local communication between the sender and receiver.
Use the intended household network
If you administer the router, follow its documentation for device isolation and casting support. Moving trusted devices onto the main network can be simpler than weakening the guest network used by visitors.
Keep security boundaries deliberate
A hotel, office or shared building may intentionally block local discovery. Do not attempt to bypass its controls. A supported cable connection or playback directly on the screen may be more practical than changing a network you do not own.
