Win10 cannot connect to synology nas with 6613 acronis in file explorer

I upgraded 3 computers to win10 pro. 2 cannot see the synology nas in file explorer in the left panel. And connot see it in acronis either, or use the device thru acronis. 1 win10 upgrade does have the synology nas listed on the left panel and can be connected to and browsed in file explorer. A backup was successfully made. Probably a service issue but I am at a loss as to what the problem might be. Any ideas? Regular 'settings' look the same for all 3 computers.