Cannot connect to 5.1 vCloud instance from plugin

I am trying to use the vCloud Director plugin and am having an issue getting the login to work.

When I give it the credentials, the plugin responds with "API version information failed to be obtained for host https://..."

I can log directly into the vCloud organization using the same credentials.

Notes:

1. Basic Authentication with Shared Session
2. VCO version 5.1.0 build 2725
3. vCloud Director version 1.5.1.622844
4. VCO was installed using the appliance.
5. vCloud Director plugin 5.1.538
6. I am using the appliance OpenLDAP and Postgres database
7. I can connect to my vSphere instance just fine.

Any help would be appreciated. I am running out of ideas at this point.

Thanks

David