we have new LMS 3.1 the snmpwalk option on device center is not working on all devices, say "please wait" but stay like that for 3-4 minutes then go. from the server itself snmp working without a problem.
What was your starting OID? It can take a LONG time for SNMP Walk to return if you do not choose a starting OID, or if your starting OID is too shallow in the MIB tree. Try a more specific OID like ifTable or system.