Your code attempts to use Windows impersonation to access the cloud-based Dynamics 365, which is totally different from on-premises Dynamics. Cloud-based Dynamics 365 does not support Windows Authentication or Windows Identity-based impersonation for authentication. Instead, it relies on OAuth 2.0 for authentication, which requires an Azure Active Directory (AAD) registered application, so you have to use one of the authentication mechanism mentioned here: https://learn.microsoft.com/en-us/power-apps/developer/data-platform/authenticate-oauth

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