protected function showLtiErrorPage() {
        if (isset($this->requestParams[LtiLaunchData::TOOL_CONSUMER_INSTANCE_NAME])) {
            $this->renderer->setData(
                'consumerLabel',
                $this->requestParams[LtiLaunchData::TOOL_CONSUMER_INSTANCE_NAME]
            );
        } elseif (isset($this->requestParams[LtiLaunchData::TOOL_CONSUMER_INSTANCE_DESCRIPTION])) {
            $this->renderer->setData(
                'consumerLabel',
                $this->requestParams[LtiLaunchData::TOOL_CONSUMER_INSTANCE_DESCRIPTION]
            );
        }

        if (isset($this->requestParams[LtiLaunchData::LAUNCH_PRESENTATION_RETURN_URL])) {
            $returnUrl = $this->requestParams[LtiLaunchData::LAUNCH_PRESENTATION_RETURN_URL];
            $serverName = $_SERVER['SERVER_NAME'];
            $pieces = parse_url($returnUrl);
            $domain = isset($pieces['host']) ? $pieces['host'] : '';
            if ($serverName == $domain) {
                $this->renderer->setData('returnUrl', $returnUrl);
            }
        }

        return $this->renderLtiErrorPage($this->exception, false);
    }