You should update your unsupported server.
To get your laptops to connect, you need to enable the insecure SMB1 on the laptops.
Control Panel
Programs and Features
Turn Windows features on or off
SMB 1.0/CIFS File Sharing Support
Uncheck SMB 1.0/CIFS Automatic Removal
Check SMB 1.0/CIFS Client
Check SMB 1.0/CIFS Server (only if you need to see Win10 shares from an old OS)
You should update your unsupported server.