The following are simply impeded from receiving orders: 1/ a man who has a wife, unless he is legitimately destined to the permanent diaconate; 2/ a person who exercises an office or administration forbidden to clerics according to the norm of cann. 285 and 286 for which he must render an account, until he becomes free by having relinquished the office or administration and rendered the account; 3/ a neophyte unless he has been proven sufficiently in the judgment of the ordinary.
Source: Code of Canon Law (Vatican.va)