why can you get a work permit for some players but not others?

[lfcfan20]

possibly a stupid question but i signed nicolas lopez from udinese on a pre contact but he failed his permit so ive loaned him out and now 120 days have passed and i applied again but the permit is still getting rejected

ive signed araujo and elkeson and didn't really have a problem getting there permits but with Lopez i cant for some reason im derby by the way in my third season

 

[mersk]

Work permit requirements for England:

1) A player must have played for his country in at least 75% of its competitive A team matches of which he was available for selection, during the two years preceding the date of the application.

2) The player’s country must be at or above 70th place in the official FIFA world rankings when averaged over the two years preceding the date of the application

Or

They must be classified as an exceptional talent. Usually only applied to youngsters who are not old enough to have established themselves in their national team.