Transfer Randomly Fails

In the last month or so, transfers often fail the first time they are in the queue. Once it fails and I process the file again (or it is processed automatically) the upload proceeds just fine. Here is an example:

[20:05:13] Operation Begin
[20:05:13] CWD /directory/uploadedto/file.html
[20:05:41] Server closed connection
[20:05:42] An established connection was aborted by the software in your host machine.
[20:05:42] Transfer failed.
[20:05:42] Operation End
[20:06:12] Operation Begin

After this, it uploads just fine. While this does appear to be a server issue, I was hoping for some insight of where I could start looking to fix this. It happens about every 1/10 uploads.

I'm using Pure-FTPD on cPanel. I've tried this on another Internet connection as well. Thanks for any help you can provide.

The problem is most likely that SmartFTP never receives the "close" event from the server and therefore believes that the connection is still alive. Only until after it sends another command it is being notified that the connection is closed. Conclusion, it's a network issue.