Error 42000: An error returned while calling VNXe api

Hello,

I have been trying to integrate CoprHD with Openstack Ocata. I have successfully added coprHD as Cinder Volume Backend and I'm able to create new volume as well as attach it to an instance. The problem occurs while detaching it. Please see screen below when which shows this error when I try detaching the volume from horizon.

After multiple days of troubleshooting Im unable to detect what the problem might be. Any help on this would be greatly appreciated. Thankyou.