Leicester thought they had beaten the August 31 deadline to sign Silva as a replacement for Danny Drinkwater, whose move to Chelsea was also confirmed after the 11pm cut-off.
The FA immediately forwarded the deal to FIFA’s Transfer Matching System, which was rejected by the world governing body because the deadline had passed.
A FIFA spokesman said: “We can confirm the following decision of the Single Judge of the Players’ Status Committee: the petition made by the Football Association for permission to request the International Transfer Certificate for the player Adrien Silva and subsequently register the player for its affiliated club, Leicester City FC, is rejected.”
Sky Sports reports Leicester were frustrated in the delays in transfer papers reaching them but that they were completed and signed within minutes upon arrival.
Leicester officials were confident the papers were sent before the midnight deadline, with a one-hour extension having been granted by FIFA for the international transfer.
But the Transfer Matching System (TMS) – which links clubs with the FA, other governing bodies and FIFA, showed the documents were late in arriving.
Silva recently attended Leicester races with the Foxes players.
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