After upgrading to Windows Server 2022, you cannot access insecure shares

Add the following Registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters
AllowInsecureGuestAuth DWORD Value 1

Add it through PowerShell:

New-Item -Path 'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters' -Name AllowInsecureGuestAuth -PropertyType DWORD -Value 1