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Authenticating with Microsoft to receive an Access Token is well documented here:
https://docs.microsoft.com/en-us/azure/active-directory/develop/msal-overview
More than likely you will want to use the AuthenticationContext.AcquireTokenSilentAsync method:
https://docs.microsoft.com/en-us/dotnet/api/microsoft.identitymodel.clients.activedirectory.authenticationcontext.acquiretokensilentasync?view=azure-dotnet
Depending on the authentication flow for the scenario being implemented you will need some or all of the following information:
Authority: https://login.microsoftonline.com/common
iTWOcx Resource: 52e5f8a4-8b0e-455f-9df4-5beb7c37dd18
ClientId: (GUID of the application configured for SSO in your Azure AD tenant)
ReturnUrl: https://au.itwocx.com/cxR/Authentication
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