This issue may be caused by an improper MTU setting and the system is unable to communicate with our server.
Step 1. Run ipconfig from command prompt to verify default gateway address. (Usually 192.168.1.1)
Step 2. Log into the router interface by typing default gateway address into Internet Explorer address bar (192.168.1.1)
Step 3. For Linksys routers the default username and password is admin for both entries. If user has changed this you will need to know what it is and type it in.
Step 4. Enable MTU and change the size to 1470. To find to optimal MTU settings refer here.
Step 5. Retry downloading or updating the software.