You have an on-premises AD DS domain with a Windows Server named Server1 that runs IIS and hosts a web app App1 using Windows authentication. You want to migrate App1 to Azure App Service and enable Windows authentication there. Which setting should you configure first?

To enable Windows authentication for an Azure App Service, the user accounts that App1 relies on must exist in Microsoft Entra ID. Directory synchronization with the Microsoft Entra tenant ensures that your on-premises Active Directory users and groups are replicated to Microsoft Entra ID. Without these synchronized identities, the App Service cannot authenticate users against your on-premises domain. COM and COM+ components are legacy technologies not directly related to enabling Windows authentication for an Azure App Service. Port bindings are configured within IIS on the server, not a prerequisite for App Service Windows authentication. HTTPS bindings and SSL are crucial for secure communication but do not enable the authentication mechanism itself; they secure the channel over which authentication occurs.