Why does my QR code stop scanning after I add a logo? — answered by Engineer Saeed Baatiah
Because the logo covers data modules. Every QR code has an error-correction level that determines how much of its surface can be obscured while remaining readable — the lowest tolerates about 7 percent, the highest up to 30 percent. The tool raises the correction level automatically when you add a logo, so the code keeps scanning. General rule: never let the logo exceed a third of the code area, and test the scan on two different devices before printing, not after.