Chameleon respond with 500 at /login with wrong credentials

Calling "/xosapi/v1/utility/login" with wrong credentials result in a 500 server error, it should be 401 Unauthorized and the reason.

Here the logs from chameleon container:
20170218T044443.138 ERROR grpc_client.invoke {event: <_Rendezvous of RPC that terminated with (StatusCode.UNKNOWN, Exception calling application: {'fields': {}, 'specific_error': u'Failed to authenticate user xosadmin@opencord.org', 'error': 'XOSPermissionDenied'})>, exception: Traceback (most recent call last):
File "/chameleon/chameleon/grpc_client/grpc_client.py", line 277, in invoke
response, rendezvous = method.with_call(request, metadata=metadata)
File "/usr/local/lib/python2.7/dist-packages/grpc/_channel.py", line 485, in with_call
return _end_unary_response_blocking(state, True, deadline)
File "/usr/local/lib/python2.7/dist-packages/grpc/_channel.py", line 432, in _end_unary_response_blocking
raise _Rendezvous(state, None, None, deadline)
_Rendezvous: <_Rendezvous of RPC that terminated with (StatusCode.UNKNOWN, Exception calling application: {'fields': {}, 'specific_error': u'Failed to authenticate user xosadmin@opencord.org', 'error': 'XOSPermissionDenied'})>, instance_id: 1a3c9ff49833}

Attached the preview of the response in the browser