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Devices this browser can see
MicrophonesMICCamerasCAMAudio outputsSPKGamepadsPADTap a line to open that test.
Labels follow your keyboard layout where the browser allows it.
MIC-E1The browser never asked for permission
Fix You (or the browser) blocked it earlier. In Chrome or Edge, click the icon at the left of the address bar, set Microphone to Allow and reload. In Firefox, click the crossed-out microphone in the address bar. In Safari on Mac, go to Safari › Settings › Websites › Microphone. On iPhone, open Settings › Safari › Microphone.
MIC-E2Permission is allowed but the meter stays flat
Fix Check the hardware mute switch on the headset or cable, and that the right input is chosen in the list. On Windows, open Settings › System › Sound › Input and check the volume and that the device isn't disabled. On macOS, check System Settings › Sound › Input and Privacy & Security › Microphone for your browser.
CAM-E1Black picture but the camera light is on
Fix Many laptops have a sliding privacy shutter or a camera key (look for a camera icon on F8, F10 or the Fn row). Some Lenovo and HP models also have a software kill switch in their vendor app.
CAM-E2"Device is busy" or the camera won't start
Fix Only one app can use most webcams at a time on Windows. Close Zoom, Teams, Skype, OBS, the Camera app or other browser tabs using the camera, then press Start again.
SPK-E1Left and right are swapped
Fix Check the plugs on the back of the speakers or the L/R marks on the headphones. On Windows, open Sound settings › your device › Properties and turn off any "swap channels" option in the driver's audio app. Bluetooth headsets sometimes swap channels after a firmware update.
SPK-E2Sound comes from both sides on Left
Fix Mono audio is turned on. On Windows: Settings › Accessibility › Audio › Mono audio. On macOS: System Settings › Accessibility › Audio › Play stereo audio as mono. On iPhone/Android, look under Accessibility › Audio.
KEY-E1A key doesn't light up at all
Fix Try it in a plain text editor. If it fails there too, it's the switch or the keyboard matrix. On laptops, Fn-locked rows (F1–F12) may send media keys instead: toggle Fn Lock (often Fn + Esc) and retry.
KEY-E2Windows key, Print Screen or Fn don't register
Fix Some keys never reach a web page. The operating system catches Windows/Command, Print Screen and certain media keys, and Fn is handled inside the keyboard itself. That's normal and not a fault.
MSE-E1Single clicks count as double-clicks
Fix That's switch chatter, the most common mouse fault. The metal contact inside the switch has worn and bounces. Compressed air sometimes helps for a while; the lasting fix is replacing the switch or using the warranty. Some gaming mice have a debounce-time setting in their software.
MSE-E2Right-click opens a menu
Fix The test pad blocks the context menu. If one still appears, your mouse software may be remapping the button.
PIX-E1Is it dead or stuck?
Fix A dead pixel is black on every colour: no power reaches it, and it's rarely fixable. A stuck pixel shows one colour (red, green, blue or white) all the time; it's a sub-pixel stuck on and can sometimes be revived with the flasher or gentle pressure through a soft cloth.
PIX-E2Full screen doesn't cover the whole display
Fix On iPhone, Safari doesn't allow full screen for web pages; the test fills the window instead. Rotate to landscape and scroll so the address bar shrinks. On desktop, make sure browser zoom is 100%.
PAD-E1The controller isn't detected
Fix Press a button after the page has loaded: that's required. Try a different USB cable (many are charge-only) or port. Close Steam if it's running, since Steam Input can take over the controller. Switch Pro and some generic pads only work in Chrome or Edge.
PAD-E2Buttons are in the wrong place
Fix If Mapping says non-standard, the browser doesn't recognise the layout and lists raw buttons by number. That's common with older generic pads and some Bluetooth modes; games may still map them correctly.