Everton have not been granted clearance to sign Belgium international Vadis Odjidja-Ofoe on loan from Club Brugge.
FIFA has refused to ratify the transfer, which included an option for a permanent deal. Everton, who insist they submitted the necessary paperwork in time, are now weighing up the options available to them.
The Toffees said in a statement: "FIFA has today refused to ratify the loan transfer of Vadis Odjidja-Ofoe to Everton from Club Brugge.
"The decision comes despite both the Football Association and Premier League giving their full support to the loan agreement and Everton lodging the relevant signed paperwork in advance of the international transfer deadline on August 31.
"An Everton spokesman confirmed the club will consider all available options before making any further comment."