Dallas Mavericks owner Mark Cuban believes that fantasy sports is a game of skill and an attorney general from his hometown is wrong to declare it as illegal gambling.

The Fantasy Sports Trade Association (FSTA) convention is usually held in Las Vegas but after Nevada required fantasy sports operators to secure a gambling license to operate, the organizers decided to move to a friendlier state, Texas, which has approximately 4 million daily fantasy sports players.

The two-day event started on Tuesday, the same day as Texas’ Attorney General Ken Paxton released an opinion saying daily fantasy sports rely too heavily on chance to be considered games of skill, thus qualifying the games as a form of betting under Texas state law.

Cuban, who has invested in two fantasy sports startups earlier this month, booed Paxton and tweeted,  “What a disappointment re DFS. You certainly don’t represent the views of Texans.”