You notice your AD gateway sync in ICDm is available up and running but the sync showing the following error: Topology Fail:
Issue is due to a client defect installed on the AD server causing the communication towards: uploads.sep.securitycloud.symantec.com:443 to fail hence the the error above.
AD on premise.
Make sure connection is working towards the URL: uploads.sep.securitycloud.symantec.com:443 as well interception is disabled to avoid the issue.
If issue persist please contact Symantec support for further guidance.