@Jennifer Parsons Thanks for posting in our Q&A. From your description, I know that the App and browser isolation policy is not applicable to the device.
Generally, "Not applicable" means that the policy is not supported on the device. To clarify this issue, we appreciate your help to collect some informmation:
- Make sure that the device is the supported system. Please refer to the following article to check.
https://learn.microsoft.com/en-us/windows/security/threat-protection/microsoft-defender-application-guard/reqs-md-app-guard - Make sure that Microsoft Defender Application Guard is installed.
If there is anything update, feel free to let us know.
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