Whether you need to remove your phone case depends on its material, thickness, and the performance of your phone's NFC antenna. If your case is made of plastic, silicone, or other non-conductive materials, you should be able to scan the sensor without removing it. If your case is made of aluminum, metal, or has a conductive surface, you may need to remove it before scanning the sensor. A thick case may also obstruct the phone's sensor scanning.