Your proxy/firewall may have a timeout setting or you may only be allowed to download a certain number of bytes through your proxy/firewall. Contact your system administrator to increase the setting.
In order to resume interrupted downloads, your Web client, your Web proxy server (if used) and our server must all support "byte-range serving". Our servers support this, you can use any download utility to resume interrupted downloads. Some browsers are also able to resume interrupted downloads.
The URLs used to access our site are only valid for a number of hours. An attempt to download a file after the URL has expired will result in a redirection back to the web site you entered through. The download utility will consider this a failure and continue to retry. In order to resume an interrupted download with an expired URL you must first use your Web browser to navigate back to the web site that displayed the download. Then the download utility will be able to resume the transfer. Also, some companies utilize a cache server in conjunction with proxy / socks. If your download utility is making a "byte-range call" for part of a file, the cache server may ignore this because it thinks it needs to cache the entire file. Your download utility would appear to hang until the cache server gets the portion of the file you requested.