Floyd Mayweather Jr. may have managed to notch his 50th career victory with a 10th-round TKO over Conor McGregor, but the undefeated world champion has failed to do one thing Saturday night: bet on his fight.

The five-division boxing champion, who is known for betting big bucks on sporting events, earlier promised to place wager—on himself, of course—on his match against the UFC star. And that he did, according to ESPN’s David Purdum.

Purdum quoted multiple sources who said that “Mayweather attempted to place a $400,000 bet on the fight ending under 9.5 rounds at -200 odds” at a sportsbook at the M Resort in Las Vegas several hours before the fight took place.

However, “there were concerns over the legality of a fighter betting on anything other than a straight win,” which prompted Mayweather to wager instead on himself winning by a knockout. But because he had to wait to place a wager, a reportedly “pissed” Mayweather “left without getting the bet down.”