Symptoms: device list is empty.
Possible causes: USB debugging disabled, cable/driver issue.
Fix: reconnect cable, try another cable, run adb devices.
Possible causes: permission prompt not accepted, incompatible resolution.
Fix: accept prompt, lower resolution / FPS in settings, retry.
Possible causes: USB 2.0, high CPU load.
Fix: use USB 3.0, reduce quality, close background apps.
Possible causes: remaining time is 0, or your client version is blocked.
Fix: update client, watch a rewarded ad to extend time.
Symptoms: the client reports multiple devices and refuses to start streaming.
Fix: disconnect extra devices and keep only one device connected.