There is a scenario that I'm working on and that is clustering Consul for Service Discovery. I have 3 physical machines to create a cluster. I follow this tutorial to design my cluster. At the end of the day, this is the result of consul members:

** I don't see the leader election or something like that, strange!!
There is an error on connection to Consul UI, as long as I enabled ui in the configuration. The error said
The Backend responded with an error, Error 500 You may have visited a URL that is loading an unknown resource, so you can try going back to the root or try re-submitting your ACL Token/SecretID by going back to ACLs.
Then I realized may it's important to configure ACL, so I added these lines to my configuration file
acl {
enabled = true
default_policy = "deny"
down_policy = "extend-cache"
}
After this consul members command said
Error retrieving members: Unexpected response code: 403 (ACL not found)
and consul acl bootstrap command said
Failed ACL bootstrapping: Unexpected response code: 500 (The ACL system is currently in legacy mode.)
Good to mention that all the configuration for servers is coming from this tutorial.
So what's going on here?