See
Win11 24H2 Installed, now no network sharing https://www.elevenforum.com/t/win11-24h2-installed-now-no-network-sharing.29035/
especially this -
Computer Configuration, Windows Settings, Local Policies, Security Options
Double click on Microsoft Network Client: Digitally sign communications (always)
Double click on Microsoft Network Client: Digitally sign communications (if server agrees)
Set both of these to "Disabled"
Click on OK.
Please let us know if this helps.