"Your Internet shit". Firewall, RCN, anything. There in the window below and the solution method are given.
Sean_Rolfs answered on June 27th 19 at 15:03
Try to follow the link: https://unity3d.com/ru/get-unity/download/archive?...
Locate all versions of the engine that are necessary to You personally version (as I understand it is 5.6). To the right of the engine there is a dropdown list "Download Win" is the loading of the components to Unity. Select the required component. If you want to download Unity torrent with .torrent file. A link to it in the same dropdown list.
If anything, write to community. Reference: https://unity3d.com/ru/community