看看这样的Log文件表示什么意思

[05/09/17 16:01:29][network detector] resetting the qt network access manager
[05/09/17 16:01:33][network detector] got a network failure
[05/09/17 16:01:33][api] network error for http://xxx.xxx.com:8000/api2/ping/: Connection closed

[05/09/17 16:02:02][network detector] resetting the qt network access manager
[05/09/17 16:33:34]failed to read request from shell extension: ???

[05/09/17 16:34:43]failed to read request from shell extension: ???

[05/09/17 17:30:19]failed to read request from shell extension: ???

我把网站地址用X代替了, 下面的问号是applet.log中本来就是这个样子, 不知道什么意思, 但似乎不影响同步