My suggestions may or may not provide an answer for @Ahmed, but they seem to work in resolving SecureDownloadManager download problems for me.
SecureDownloadManager needs admin privileges
I've found that when my download stalls, even after many restarts, it has been due to SecureDownloadManager not having admin privileges (which I often forget about at the time). When I've restarted SecureDownloadManager with the option to Run as Administrator it has managed to pick up where it left off and it completes the download process.
The following info is for Windows 8.1:
The problem is in finding SecureDownloadManager.exe. If you have a link in the start menu, right click on the tile and select Open file location. Then right click on the link and select Properties. You'll find the location of SecureDownloadManager in Start in: If you don't have a link you can find SecureDownloadManager in the registry by searching the keys for SecureDownloadManager and getting the execution path for it. In my case it was in,
C:\Users\raymond\AppData\Local\e-academy Inc\SecureDownloadManager
Of course you need to enable hidden folders to get to the AppData folder. When you find SecureDownloadManager.exe right click on it, select Properties, click on the Compatibility tab, check the box, Run this program as administrator, click Apply, then Ok.
This is a programming problem
As to why the problem with SecureDownloadManager has persisted for so long is anybody's guess. But I do know I've wasted a lot of hours on this problem and I know I'm not alone. It does, however, serve as a good example of how not to program, eh?
I have to disagree with @Dukeling. This question is on-topic in a programming forum because many, many computer programming students are wasting their time with failed downloads when they could be busy programming. If you can't get the tools you can't program.
My latest case was in downloading a copy of Windows Server 2008 R2 to install in a virtual instance to isolate testing of software in a particular environment. So downloading an os, at least in my case, qualifies as a programming task.