A. Please check whether the top cap of the tank is installed in place. If the tank is not covered tightly immediately after e-liquid filling, it can easily cause a large amount of air to enter the tank leading to leakage. B. Please check whether the coil is installed in place. C. If the tank is not used for more than 3 days after being filled with e-liquid, it can easily lead to leakage. D. If the device is placed in a high-temperature environment or under direct sunlight outdoors, such overexposure can easily lead to leakage. E. It is not recommended to use the device in an airplane or a negative-pressure environment. The inconsistent internal and external pressure can result in the leakage of the tank. F. Dropping the tank on the ground can easily lead to leakage.