Starting in Configuration Manager version 2509, the AdminService now rejects NTLM authentication attempts. The SMS Provider provides API interoperability access over HTTPS, called the administration service. Configuration Manager uses the administration service REST API in several native scenarios. You can also use the administration service for your own custom scenarios.
After upgrading to version 2509, the NTLM authentication is rejected by Admin Service. The AdminService.log should write the below message when NTLM authentication is attempted "Rejecting NTLM authentication."
After upgrading to version 2509, the NTLM authentication is rejected by Admin Service. The AdminService.log should write the below message when NTLM authentication is attempted "Rejecting NTLM authentication."