Unable to download the file when updating/installing apps (not always)

I keep randomly getting this error for various apps, before it was Firefox when I tried updating it, now it was Notepad2 while Notepad++ installed just fine in same batch install of 2 apps. I don't have any proxy or network issues and I don't know why would hosting server not permit the download for my location as popup mentions. I've also checked my DNS logs and there is nothing being blocked there.

Why is this happening?