WBA lightweight champion Jorge Linares has been given 30 days to arrange a fight against Britain's Luke Campbell.
Campbell, 29, has yet to fight for a world title, but is the mandatory challenger having beaten Darleys Perez of Colombia in April.
Venezuelan Linares, 31, beat Briton Anthony Crolla last year to claim the title and also won a rematch in March.
The WBA said Linares "must face his mandatory opponent in a period of nine months" from winning the belt.
They added that that time "expired on 23 June 2017".
The governing body said both teams had been notified and set a deadline of 30 days from 21 July to reach an agreement.
Campbell, who won gold at the 2012 Olympics in London, has had 18 professional fights, winning 17 and losing once.
It will be his first world title shot.
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