Lee Selby's world-title elimination fight with George Kambosos in Cardiff has been cancelled.
Selby was due to fight the unbeaten Australian with the winner taking on IBF lightweight champion Teofimo Lopez.
The Welshman, who is bidding to become a two-weight world champion, has seen the fight postponed twice because of the coronavirus pandemic.
It had been hoped the contest would take place on 3 October at the Motorpoint Arena, with fans.
That has not proved possible and the contest will now go back to purse bids after the respective management teams failed to renegotiate terms, Matchroom have confirmed to BBC Sport Wales.
Selby moved up to lightweight after losing his IBF world featherweight title to Josh Warrington in 2018.
The 33-year-old revealed after the split decision points defeat at Elland Road that he was so drained at featherweight that he would chew but not swallow food to make the weight.
He has won both his lightweight fights, defeating Omar Douglas and Ricky Burns in 2019.
Selby and Kambosos were set for the first headline fight in Wales since Anthony Joshua beat Joshua Parker in a heavyweight world title contest at the Principality Stadium in March 2018.