have you verified the interoperability between the NSX and Usage Meter versions?
It seems that Usage Meter 3.6 cannot meter NSX 6.2.3 - > VMware Product Interoperability Matrices.
For more interoperability information about Usage Meter, see Interoperability Pages for vCloud Usage Meter 3.6.
Hope this helps.
Thank you for your reply.
The Usage meter has been updated to the latest version.
And.... next time I check the interoperability Matrices.... ( ahum )