Master in Sexology and Psychosexual Counseling. For More Info WhatsApp- 9604715783/9359863878. Causes of Erectile Dysfunction · Venous Leak: If the blood vessels (veins) which normally compress during an erection do not fully compress, an erection may not be attainable or may not last long. This can be caused by injury or diseases which prevent the full expansion of the vessels (arteries), which normally expand with blood.