Unemployment is high in iran among young men due to their lack of skills. what could be one cause for this problem?

I believe the answer is lack of investment in human capital 
In order to increase the quality of the labor, it is important for Government to invest in Human capital (such as giving free tuition or some sort of  job training).
Even though this type of investment may increase the national debt in the beginning, it would be paid off in the long run because of the increase in GDP.