Device Stuck in "All Learning Devices in Inventory Services"

[xuxiang_cctv]

LMS Version 4.2.5

one 6509 stuck in "All Learning Devices in Inventory Services"

    *** Data Collector Status Information ***
 Discovery Progress    = 10% completed
 Error Code                   = N/A
 Error Message             = N/A

I have remove this device and add again,and also adjust the snmp timeout ,this device still stuck in learning state.

But,this device inventory collection and config archive function is ok.

Is this a bug,or how can I do next?

[AFROJ AHMAD]

Is it happening just for a single device ?

are all the other devices are in KNown status .

Any firewall between this device and LMS ?

Thanks-

Afroz