Android
Connect to a New Wi-Fi Network auf Android
Android forgets or fails to auto-join a network whenever a router is replaced, a password changes, or the network is not broadcasting its name. The phone keeps scanning for networks it already knows, but a new access point has to be added manually before it shows up as connected.
Each Wi-Fi network is stored as its own profile, including security type and password. That is why switching routers or renaming a network always triggers a new setup instead of reusing an old entry.
Menu path
Open Settings ➔ Network & internet ➔ Internet ➔ pick the Wi-Fi network from the list ➔ enter the Wi-Fi password ➔ tap Connect.
If the network was already set up before but still will not connect, forgetting it first usually clears a mismatched password faster than retyping it. Use this only when a fresh join does not resolve the problem, since it removes the saved profile completely.
Joining an open public network skips the password step entirely, but traffic on that network stays unencrypted unless the app or site itself secures the connection.