Incorrect DCOM enabled for WMI connections
If DCOM is not enabled, WMI will not be able to connect to remote devices to scan.
Below steps shows to configure DCOM
Double-click Component Services > Double-click Computers > Right-click My Computer
Select Properties > Select Default Properties tab
Enable Distributed COM on this computer checkbox is checked
Default Authentication Level: Connect
Default Impersonation Level: Identify
Click on COM Security tab > Click Edit Limits under “Launch and Acitvate Permissions”
Make sure Remote Launch and Activation permissions are enabled for the Administrators group
Restart remote device
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole,EnableDCOM. If the value is “N”, then you need to change it to “Y” and reboot.
Ports to check in firewall
Inbound TCP : 135,445,1024-2000 Dynamic Ports
Inbound UDP : 137