There may be several reasons:
1. Wireless charger failure: The wireless charger may have hardware faults, such as coil damage, power adapter failure, etc., resulting in normal charging.
2. iPhone 12 charging port failure: If your iPhone 12 charging port has problems, such as dust or dirt blockage, damage, etc., it may also cause wireless charging to fail to charge.
3. Wireless Charger is not compatible with iPhone 12: If your wireless charger is not compatible with iPhone 12, it may not charge properly.
4. Wireless charger is too far away from iPhone 12: If your wireless charger is too far away from iPhone 12, it may not charge properly.
5. Low battery: If your wireless charger is low, it may not be able to properly charge your iPhone 12.
Apple 12 does not charge third-party charging devices without Apple certification