Clinically men can’t get an erection is called erectile dysfunction. It may be caused by psychological factors, low libido, vascular impotence and other reasons. 1. Psychological factors: If a man is overly nervous and anxious during sex, it may cause the arteries supplying blood to the penis to constrict, and the blood supply to the corpus cavernosum of the penis to decrease, resulting in the corpus cavernosum of the penis not being able to get an erection. 2. Low libido: Low libido is one of the common sexual dysfunctions in men. Due to the low level of testosterone, resulting in a decrease in libido, men will also be unable to get an erection. 3. Vascular impotence: Due to insufficient blood supply to the arteries or damage to the blood vessels in the cavernous body, men cannot get an erection. When men can’t get an erection, they should go to the regular hospital in time to find out the cause of the disease and give targeted treatment under the guidance of professional doctors.