Hi JJape, Welcome to Meraki Community 🙂   Please, provide more detail information: Can you send a screenshot of the WMI error message on the Dashboard? What's the EventID # in Event Viewer on the AD Server? Is the AD Server located locally on the network or via VPN Tunnel? Have you taken any packet capture on the relevant interface on the MX, and filtering it for port <3268>?   Point 1 - Check the requirements - https://documentation.meraki.com/MX/Content_Filtering_and_Threat_Protection/Configuring_Active_Directory_with_MX_Security_Appliances#Configuration_Overview Point 2 - Make sure that the domain admin account is a member of the Domain Admins group in Active Directory Point 3 - Certificate Requirements for TLS Point 4 - If the Server IP address is located over a VPN Tunnel, communication with the server will originate from the highest numbered VLAN included in the VPN.   WMI Error message - have your performed the following tests: TEST 1 - "Domain Admin" field - only <username> - https://documentation.meraki.com/General_Administration/Tools_and_Troubleshooting/Active_Directory_Issue_Resolution_Guide TEST 2 - "Domain Admin" field - <domain\username> - https://community.meraki.com/t5/Security-SD-WAN/Configuring-Active-Directory-Authentication/m-p/203532/highlight/true#M46820   If you have any questions, please don't hesitate to contact us. ... View more