Cannot add controller replica to the existing UCP cluster

Question

I have UCP cluster with 3 controllers and 3 regular nodes. I was able to successfully setup the cluster the first time. However, I am trying to do a fresh-install on one of the controllers but i am getting the following error while running the join command:

a
INFO[0001] Verifying your system is compatible with UCP
INFO[0001] Checking that required ports are available and accessible
INFO[0117] Starting local swarm containers
INFO[0120] Starting UCP Controller replica containers
ERRO[0120] Server response: {"message":"etcdserver: peerURL exists"}
ERRO[0120] Failed to start KV store.  Run "docker logs ucp-kv" for more details
FATA[0120] Failed to add member to KV store: {"message":"etcdserver: peerURL exists"}

I am running the following join command:

docker run --rm -it \
  --name ucp \
  -v /var/run/docker.sock:/var/run/docker.sock \
  docker/ucp:1.1.3 \
  join --replica --interactive