Error trying to add a host to Rancher 2.0 beta4

Hi,

First, I am totally new to Rancher and Kubernetes. We have a small, bare metal cluster. I setup a separate machine with Ubuntu 16.04 and installed docker and rancher 2.0 beta4. I then tried to add our cluster master node to rancher as an etcd and controlplane host by running the generated command on the master node.

Everything seemed to be going well. Provisioning and health checks were going fine until I got this error:

Waiting for API to be available; exit status 1, W0427 07:11:50.589641 986 factory_object_mapping.go:423] Failed to download OpenAPI (the server has asked for the client to provide credentials), falling back to swagger error: You must be logged in to the server (Unauthorized)

I have no idea how to get past this. The thing is, I somehow managed to add the host in rancher 2.0 beta3

My cluster is behind a corporate firewall, could that have something to do with this?

Hoping someone can help!