When running an Endpoint Discover scan, it appears to time out frequently.
This can be caused if scan has been ran on a Friday, or Weekend when most user systems are powered off, or unavailable to run the Endpoint Discover Scan.
Increasing the timeout settings for Endpoint Discover scans to allow sufficient time for agents to check in and run the scan can assist in resolving this issue. As well as running the Endpoint Discover scan when users machines are more commonly online.