A statement on Fulham's website read: "On Thursday morning, following talks with Ajax, the club can confirm that it has ceased negotiations for the release of Martin Jol from his contract with the Dutch club.
"Subsequent negotiations revealed that the clause was no longer valid and Ajax remained steadfast in their desire to keep their manager, therefore dialogue between the two clubs has now ended."
Ray Lewington will remain in caretaker charge but, with the new Premier League season starting in less than four weeks' time, Fulham are under pressure to get a new man in.
"Since Roy Hodgson indicated that he wanted to leave Fulham, a short list of potential managers was identified, and the club is committed to ensuring that the right candidate is brought on board to continue the club's progress, in the soonest timeframe possible," said the statement.
"The chairman and CEO would also like to personally thank Ajax for their conduct throughout this very public process.
"Ray Lewington will remain in charge of all first-team matters as caretaker manager and the club would like to thank Ray, his backroom staff and all the players for their patience and professionalism ahead of the 2010/11 Barclays Premier League season."