Since I have started using Windows more I have run into this problem a few times. Sometimes it can be a driver issue but that has never been the case for me. It is usually I didn’t pay attention during the install and selected Public by accident or Windows is acting weird and switched an existing network to Public. This will fix the problem if nothing else works and you think your system is sane.
Start up Powershell
Just search for it if you don’t know where to find it under the start menu.
Check the current adapter settings
run > Get-NetConnectionProfile
Name : This will vary depending on how the network is configured
InterfaceAlias : Ethernet
InterfaceIndex : 3
NetworkCategory : Public/Private/DomainAuthenticated depends on current Category
IPv4Connectivity : Internet
IPv6Connectivity : LocalNetwork
You need to remember the InterfaceIndex for the network you want to modify.
Change the current NetworkCategory
run > Set-NetConnectionProfile -InterfaceIndex 3 -NetworkCategory Private
This command will change the NetworkCategory to Private or any category you want.