public function exception($e)
    {
        $logLevel = \Psr\Log\LogLevel::CRITICAL;
        if ($e instanceof \Sabre\DAV\Exception) {
            // If it's a standard sabre/dav exception, it means we have a http
            // status code available.
            $code = $e->getHTTPCode();

            if ($code >= 400 && $code < 500) {
                // user error
                $logLevel = \Psr\Log\LogLevel::INFO;
            } else {
                // Server-side error. We mark it's as an error, but it's not
                // critical.
                $logLevel = \Psr\Log\LogLevel::ERROR;
            }
        }

        $this->server->getLogger()->log(
            $logLevel,
            'Uncaught exception',
            [
                'exception' => $e,
            ]
        );
    }