mysql issues

[brokiem]

Error: Call to a member function fetch_array() on bool
File: plugins/EconomyAPI_v3.0.0-SNAPSHOT-4f06e8d0.phar/src/onebone/economyapi/provider/MySQLProvider
Line: 116
Type: Error

THIS CRASH WAS CAUSED BY A PLUGIN
BAD PLUGIN: EconomyAPI v3.0.0-SNAPSHOT

Code:
[107]    * @return float|bool
[108]    */
[109]   public function getMoney($player) {
[110]       if($player instanceof Player) {
[111]           $player = $player->getName();
[112]       }
[113]       $player = strtolower($player);
[114] 
[115]       $res = $this->db->query("SELECT money FROM user_money WHERE username='" . $this->db->real_escape_string($player) . "'");
[116]       $ret = $res->fetch_array()[0] ?? false;
[117]       $res->free();
[118]       return $ret;
[119]   }
[120] 
[121]   /**
[122]    * @param Player|string $player
[123]    * @param float $amount
[124]    * @return bool
[125]    */
[126]   public function setMoney($player, float $amount): bool {