private function passChallenge($username)
    {
        $getdata = [
            'operation' => 'getchallenge',
            'username'  => $username
        ];
        $result = $this->sendHttpRequest($getdata, 'GET');
        
        if (!is_array($result) || !isset($result[ 'token' ])) {
            return false;
        }

        $this->serviceExpireTime = $result[ 'expireTime' ];
        $this->serviceToken = $result[ 'token' ];

        return true;
    }