Thank you for your reply in this thread and for the troubleshooting you've done so far.
First we'd like to suggest that you check if there's any pending OS updates and update to the latest.
If you have an SD card we suggest that you uninstall the app > turn off your phone > take out your SD card > turn on the phone again (without the SD card) > reinstall the app since the card can be corrupted.
If that doesn't do the trick, can you log in with your account on a different device to see if the issue persists?
We'll keep an eye out for your reply.
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Still no joy I am afraid. Have deleted the app, taken out SD card, cleared cache...re-installed and still the same. After opening the camera icon, I select "Scan" button and the camera momentarily flashes on but then goes back to the Scan button.
Any more advice or suggestions greatly appreciated.