1. Make sure current router is encrypted. Mi Home devices won't connect to unencrypted router.
2. Make sure current router doesn't require a second ID or password verification.
3. Some devices don't support 5GHz network. See manuals for the supporting network of your device.
4. Make sure no hidden SSID is set for the router. Routers with hidden SSID won't appear in the list. In that case, please modify router settings and reconnect