One possible option is that there is an issue with access right to these nodes. Try enabling "system" user
nxdbmgr reset-system-account
(it's password will be "netxms"). This account has access rights to all objects in the system. Could be that the nodes will be visible (may be in the root of object tree).
nxdbmgr reset-system-account
(it's password will be "netxms"). This account has access rights to all objects in the system. Could be that the nodes will be visible (may be in the root of object tree).
parameter.