How to Fix “adb: device unauthorized” and Offline Devices When Testing Android Games

Device deployment fails at the handshake more than anywhere else. The states have a fixed remedy ladder. Here it is, in order.

How to fix it

1. Accept the prompt properly

Unlock the phone screen, replug, and watch for 'Allow USB debugging' — check 'Always allow from this computer'. No prompt: Developer Options > Revoke USB debugging authorizations, then replug.

2. Restart the plumbing

adb kill-server && adb start-server then adb devices — stale daemons hold devices 'offline' long after the actual issue cleared.

3. Blame the cable early

Charge-only cables and flaky hubs cause offline/disappearing devices — use a short data cable direct to the machine; this resolves an embarrassing share of cases.

4. Prefer wireless for iteration

adb over Wi-Fi (pairing on Android 11+) removes the cable variable for day-to-day testing — keep USB for first pairing and big installs.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every mobile error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.