各位老师好，问下，配置kurento-repository-server后，连接linux的7676服务器后，服务器报以上异常，有谁遇到过，谢了哈
异常信息：
[http-nio-7676-exec-2] ERROR org.apache.catalina.core.ContainerBase.[Tomcat].[localhost].[/].[dispatcherServlet] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException: null
at org.kurento.repository.internal.repoimpl.mongo.MongoRepository.createRepositoryItem(MongoRepository.java:108) ~[kurento-repository-internal-6.12.0.jar!/:6.12.0]
java后台代码：
github上的kurento-repository教程原代码：
try {
Map metadata = Collections.emptyMap();
repoItem = repositoryClient.createRepositoryItem(metadata);
} catch (Exception e) {
log.warn("Unable to create kurento repository items", e);
}