@Bonus12
Thank you for posting in Microsoft Q&A forum.
May I ask how many machines you have deployed to and do they have the same deployment issue?
What is the operating system version of these machines?
Different operating systems have different needs for onboarding to ATP. Windows 8.1 and other down-level operating system devices need the Workspace key and Workspace ID to onboard. Up-level devices, such as Windows Server version 1803, need the onboarding configuration file.
If your target collection contains down-level devices, and you use the instructions for onboarding only up-level devices, then the down-level devices won't be onboarded. The optional Workspace key and Workspace ID fields are used for onboarding down-level devices, but if they aren't included then the policy will fail on down-level clients.
(1)If your target collection contains both up-level and down-level devices, It is then recommended that you use an Onboard devices with any supported operating system to ATP.
You can refer to this link for detailed steps:
https://learn.microsoft.com/en-us/mem/configmgr/protect/deploy-use/defender-advanced-threat-protection#bkmk_any_os
(2)If your collection contains only up-level devices, then you can use the up-level onboarding instructions.
You can refer to this link for detailed steps:
https://learn.microsoft.com/en-us/mem/configmgr/protect/deploy-use/defender-advanced-threat-protection#bkmk_uplevel
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