VCLOUD Director 1.5 External network creation error "failed to create external network"

Hi there all

I am in the middle of troubleshooting a problem on VCLOUD Director 5.1 that is not making any sense at all.

We are trying to create an external network. We created the PG in the VDS as required and we assigned a VLAN ID (557). Directly after that we go into the VDC interface and create an external network associated with this PG. We keep on getting the following error:

"failed to create external network as portgroup dvportgroup-124 or it's VLAN ID 557 is in use"

In use by what ? I have manually checked all the existing PG's and there is no overlapping VLAN.