Xiaomi 120w charger belongs to the high-end charger, you can check whether the internal parts of the charger are damaged. If the internal parts are damaged, it is recommended to re-purchase the corresponding brand of charger on Xiaomi's official website, and if it is within the warranty period, it can be sent to Xiaomi for after-sales repair or even replacement.
You can contact the customer service directly, tell the machine code to the customer service, he can help you find the equipment warranty period after you can give an address to replace