The built-in Barcode Reader in Custom Canvas Apps cannot scan QR codes from emails on smartphones when dark mode is enabled. The reason is that dark mode changes the background color, reducing contrast and making the QR code hard to read.

Right now, there is no way to add a white background behind the QR code to fix this issue. Asking users to switch to light mode is not a good solution, especially at events where many QR codes need to be scanned quickly.

Suggested Improvement:

• Improve the Barcode Reader so it can scan QR codes in dark mode.
• Allow developers to add a white background behind the QR code for better contrast.

If you have the same problem, please upvote this Idea so Microsoft can improve it!