Hello @Ashley Saunders,
Thank you for your time and patience while troubleshooting the issue over the call.
Error message: "Persistence of policy failed with error: Policy size is larger than allowed. Please change your targeting to fewer groups and try again".
Manage Migration status: Migration in Progress
Cause: This error occurs when the policy size of authentication methods exceeds 20kb, meaning it shouldn't include more than 18 groups.
Troubleshooting steps we took to address the issue:
- We checked modern authentication methods in your tenant to verify if any groups were added to the authentication method policies as per the above cause. However, we observed that no methods were enabled, and no groups were added to any of the policies. Please refer to the screenshot below.
- As everything appeared correct with modern authentication methods, we then verified other settings in your tenant, such as password reset and Per-user MFA service settings, but without success.
- Upon examining the registration campaign settings in your tenant, we noticed that a total of 81 users were added to the excluded users and groups, causing this issue. Please refer to the reference screenshot from my test tenant for an example.
Resolution: The issue was resolved by adding all 81 users into a single group and then adding that single group to the exclusion under the registration campaign excluded users or groups. After making this change, you were able to modify the modern authentication method policy successfully without encountering any errors.
Hope this includes all the information that you were looking for.
Please "Accept the answer" if the information helped you. This will help us and others in the community as well.
Thanks,
Raja Pothuraju.