@Support TI Thank you for your query!!!
I checked both the URL which is working completely fine for me:
https://learn.microsoft.com/en-us/system-center/vmm/vm-role-template?view=sc-vmm-1801
https://www.microsoft.com/web/downloads/platform.aspx
https://learn.microsoft.com/en-us/windows/web/
There might be some network glitch or something that's why you were getting the error. Can you please check again if it is working for you or not?
Hope it helps!!!
Please "Accept as Answer" if it helps so it can help others in community looking for help on similar topics.