Wireless charging uses the principle of magnetic induction to charge iPhone. Do not place anything between iPhone and charger. If a magnetic bracket, a magnetic shield or other object is placed between the iPhone and the charger, it may reduce the performance of the charger, or damage the magnetic strip or the RFID chip (often in some credit cards, safety signs, passports and smart keys). If you have sensitive items in your protective shell, remove them before charging, or make sure they are not between the back of the iPhone and the charger.
When connected to USB, iPhone will not have wireless charging. If your iPhone uses USB to connect to the computer, or connect to the USB power adapter, iPhone will use USB connection to charge.
If your iPhone vibration (for example, when notification is received), iPhone may shift. This may cause the charging pillow to stop providing electricity for iPhone. If this happens frequently, consider closing the vibration function, opening the no disturb mode, or using the protective shell to prevent movement.