Hi @HP Support ,
Note: For security reasons, I modified the domain name in the code you provided, please be careful not to expose any private information.
According to your description, I have some suggestions to troubleshoot our issue:
1.Please check Mailbox Features on some problematic user and make sure Default Sharing Policy and Default Role Assigment Policy are selected.
- Go to ADUC, User properties, select the Security tab and check if there are any deny options under Permissions for Authenticated Users.
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