Greetings from ManageEngine Desktop Central.
Please sync the Patch DB and then try to scan the machines. If the scanning still gets failed, then please follow the instructions from below link and share me the logs from Linux machine and DC server,
Sync DB : Patch Mgmt --> Update Vulnerability DB --> Update now.
Link below explains the log upload procedure,
https://www.manageengine.com/products/desktop-central/logs-how-to.html
Regards,
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Associate Technical Consultant
[ Desktop Management | Desktop Management for MSP | OS Deployment |
Mobile Device Management | SCCM Third Party Patch Management | Patch Manager Plus ]