"Unable to find an active license."

I'm new for LDMS and i deployed agent already. When i do an inventory scan from the core server ,

LD said "the system cannot find the path specified." so I changed to scan inventory at client that i add "/F /SYNC" on the command and it hasn't an error

when i look into ldscan>ErrorScan/errorTrans at core server.

I look at event view application, it has error that said  "Unable to find an active license. (source: LANDesk Inventory Server,Event ID: 2392)" . Why event view application

show this error?

and i 've some question that  this  problem  causes  "nothing showing in All device view " or not (it still shown in pending unmanaged client deployments ).

Could anyone help me?

Thanks.