NEW YORK – Negotiations for a third fight between unified middleweight champion Saul ‘Canelo’ Alvarez and Gennadiy Golovkin have hit some roadblocks, a source familiar with the negotiations told, putting one of the biggest fights in boxing in jeopardy.

Golden Boy, which represents Alvarez, is pushing to have a resolution by Friday or will start to look at other opponents.

Among the key sticking points, according to the source, has been the location. Golovkin has been adamant that he does not want a third fight in Las Vegas, the site of the first two matchups. Of the six scorecards submitted in the first two fights, Golovkin has won just one of them. Golovkin prefers a third fight to take place in New York or Texas. Canelo would like to complete the trilogy in Las Vegas.

In recent months, a third fight between two of boxing’s biggest stars appeared to be a foregone conclusion. Last October, Alvarez signed an 11-fight deal with DAZN that could be worth as much as $365 million. In March, Golovkin signed a six-fight deal with DAZN. Both fighters have a significant financial incentive to face each other.

DAZN, a subscription-based service, sees Canelo-Golovkin III as a major driver of new subscriptions and has been eager to set a third fight for September.

While Golovkin has been eager for a third go-round with Canelo—Golovkin called out Alvarez after his knockout win over Steve Rolls earlier this month—it’s unclear how willing Alvarez is to face Golovkin again. Alvarez has been vague about his interest in facing Golovkin, suggesting that Golovkin needs to win a title before facing him and indicating a willingness to move up in weight, which he did last December in a knockout.

“For me, [the rivalry with Golovkin] is done,” Canelo said in the ring, following his middleweight title unification win over Daniel Jacobs last month. “But if the people want another fight, we’ll do it again and I’ll beat him again.”

Among the candidates to face Alvarez in September if a deal can’t be reached are Demetrius Andrade, the middleweight titleholder who defends the lone piece of the 160-pound crown Canelo does not have on June 29th, and Callum Smith, the super middleweight champion widely regarded as the top fighter in the 168-pound division.