First check in the editor that you have the right trigger for the scene (even the Plattar team make this mistake sometimes!). Also check your internet connection on your device to make sure you can reach www.plattar.com.
If you have just uploaded your trigger, and had the app open previously, try restarting the app (swipe it off the list of running apps on Android/iOS) and scanning again. Please note it takes up to 2 minutes for new triggers to become active.
Next, check our ‘What makes a good trigger’ guide to make sure your trigger is suitable. If you saw a warning when uploading your trigger, it’s likely too low-quality to be used.
Distance and trigger size are also important factors. Ideally the trigger almost fills the width of your camera view when the user is first scanning it. If the trigger is much smaller, or much bigger (due to size or distance) you may have tracking or recognition issues.
If you find you can recognise the marker on your screen, but not when printed, try increasing the brightness of the trigger (this can happen because a screen is brightly & evenly lit, whereas printed versions will always appear darker to a camera).