A device will not connect or does not show up

The phone never appears in the device grid, vanishes after a couple of minutes, or sits there marked “Offline”. The cause is almost never the software - it is the connection: developer mode is off, the debugging prompt was never confirmed, USB is set to charging only, or the phones are not getting enough power. Work through the steps top to bottom - the first two cover most cases.

What you see in the app

The device list on the “Home” page refreshes on its own every few seconds: plug a phone in and simply wait, there is no need to restart the app. While the first scan runs, the empty screen reads “Looking for ADB devices”, and the caption below explains that the first ADB start after a computer reboot can take a few seconds.

If nothing is found, the heading changes to “No ADB devices found” and a “How to connect a phone” button appears underneath. If the computer does see the phone but cannot work with it, you also get a yellow banner along the lines of “Found phone Redmi 9A: the cable is fine, but “Allow USB debugging from this computer” was never tapped on the phone”. That banner is the most useful hint on the screen: it names both the model and the exact reason.

Step 1: turn on developer mode

This is the most common cause and it is easy to miss: while developer mode is off, the phone has no “USB debugging” option at all, and the computer will not see that phone in any form - it will not even appear in the app as waiting for authorization. The procedure is the same on every Android: tap the build number several times in a row until you see “You are now a developer”.

• Samsung: Settings → About phone → Software information → 7 taps on “Build number”;
• Xiaomi, Redmi, POCO: Settings → About phone → 7 taps on “MIUI version” (or “HyperOS version”);
• everything else: Settings → About phone → 7 taps on “Build number”.

A “Developer options” section then appears in Settings (on Samsung and Xiaomi it sits inside “Additional settings” / “Advanced settings”) - turn on “USB debugging” there. A detailed walkthrough with a menu map is in Developer mode and USB debugging.

Checklist

• developer mode is on (the step above) - without it the debugging option simply does not exist;
• USB mode is set to “File transfer”, not “Charging only”;
• USB debugging is on and the prompt for this computer is confirmed (“Always allow”);
• the cable is intact and the port works - try a different one;
• the manufacturer’s USB driver is installed on Windows;
• the hub has its own power supply and the phones get enough current;
• on Xiaomi, “Install via USB” and USB debugging in the security settings are enabled;
• the phone is unlocked, not sitting on the lock screen with the display off.

The phone is plugged in but the app does not show it

The most common case: the computer sees the phone, but debugging has not been authorized. An “Allow USB debugging?” dialog appears on the phone screen - confirm it and tick “Always allow from this computer”. The dialog is easy to miss: it disappears as soon as the screen locks. Unlock the phone, replug the cable and confirm the prompt. Whenever such devices exist, Lusiesta says so right on the connection screen.

While a phone is in that state it is listed in ADB, but commands never reach it: the grid shows an “Offline” tile with the hint “Confirm “USB debugging” on the phone”. A full trust reset helps too: “Developer options” has an item that revokes USB debugging authorizations - revoke them, replug the cable and confirm the prompt again.

What the hints on an “Offline” tile mean

When a phone was already in the grid and the link dropped, a short hint appears under the word “Offline”. Read it literally:

• “Confirm “USB debugging” on the phone” - the device is waiting for authorization. Unlock the screen and tap “Allow”;
• “No access to USB - replug the cable” - the system lacks permissions for the USB device: usually the driver, the hub or the port is to blame;
• “Replug the cable or the USB port” - the phone is on the list but does not answer commands: it fell asleep, the cable is half out, or the port sagged on power.

Firmware quirks

Xiaomi, Redmi and POCO (MIUI / HyperOS)

On these phones plain “USB debugging” is not enough. In “Developer options” also turn on:

• USB debugging (Security settings) - without it commands never go through;
• Install via USB - otherwise apps and the agent will not install;
• turn off “Verify apps over USB” / MIUI optimization if it is enabled.

MIUI requires a signed-in Mi account and an active SIM with internet access for these options - that is the manufacturer’s requirement, not ours. Once they are on, replug the cable and confirm the debugging prompt again.

Samsung

After you plug the cable in, pull down the notification shade and pick “File transfer”: in “Charging only” mode the phone will not show up in the app. On some models the mode resets on every replug. If “Developer options” has a default USB configuration item, set it to file transfer - then you will not have to pick the mode by hand every time.

If devices drop out under load

Nine times out of ten this is power or a cheap hub. Lusiesta reconnects stalled sessions automatically and keeps a short grace window after a drop so a brief hiccup does not flash statuses across the whole screen, but no software can fix a physical shortage of current. The telltale sign is exactly this: phones drop out in batches when tasks and live video run at the same time.

• use a hub with its own power adapter rather than bus power from a laptop port;
• do not hang too many phones off one hub - spread them across different USB controllers;
• swap the cables: thin charging cords cause data dropouts even when charging works fine (see USB cables: why you should not save money on them);
• in the Windows power settings, disable the option that lets the computer turn USB devices off to save energy.

A passive hub with no power supply of its own is the number one cause behind “my phones drop out by themselves”. Until power is wired properly, any setting in the phone or in the app will give random results.

How to check that it worked

1. Open the “Home” page and wait a few seconds - the list is polled automatically.
2. The phone should appear as its own tile: the number in a square badge, the serial number next to it.
3. The status is not “Offline” and the tile shows live video of the screen. If there is no picture but the device is online, that is a separate topic, see No phone preview.
4. Check that it responds: click the preview with the mouse - the tap should reach the phone.

The device number is the same everywhere in the app: “#3” in the grid, in publishing, in warmup and on the “Proxies” page is one and the same phone.

If nothing helped

Open the “Logs” page, filter by the device in question and click “Export” - you get a text file. Attach it to a ticket on the “Support” page and state the phone model, the Android version and exactly what you see on the connection screen. That way the case is solved in one pass, without a five-message thread.