There is no authority to suggest that there is a specific time when the lung meridian cannot be tapped.
The twenty-four hours are divided into twelve hours, each of which corresponds to a meridian that is relatively rich in qi and blood. But there is no saying which time can not go to knock the lung meridian.
The Lung meridian is one of the twelve meridians in the human body, originating in the middle jiao and intersecting the Hand Yangming Large Intestine meridian at the Shangyang point. The points on the Lung meridian can be used to treat throat, chest and lung diseases, such as cough, asthma, chest distension, chest pain, sore throat, shoulder and back pain, and other diseases.
However, tapping on the lung meridian has no curative effect on the disease. If you feel unwell, you should seek medical advice and treatment under the guidance of a physician, and should not try to cure the disease by tapping on the lung meridian.