$ juju list-controllers --refresh --debug
16:59:23 INFO juju.cmd supercommand.go:63 running juju [2.1.2 gc go1.6.2]
16:59:23 DEBUG juju.cmd supercommand.go:64 args: []string{"juju", "list-controllers", "--refresh", "--debug"}
16:59:23 INFO juju.juju api.go:72 connecting to API addresses: [54.153.113.36:17070 172.31.6.39:17070]
16:59:23 DEBUG juju.api apiclient.go:590 dialing "wss://54.153.113.36:17070/api"
16:59:23 INFO juju.juju api.go:72 connecting to API addresses: [jimm.jujucharms.com:443 162.213.33.250:443 162.213.33.28:443]
16:59:23 DEBUG juju.api apiclient.go:590 dialing "wss://jimm.jujucharms.com:443/api"
16:59:23 DEBUG juju.api apiclient.go:590 dialing "wss://172.31.6.39:17070/api"
16:59:23 DEBUG juju.api apiclient.go:590 dialing "wss://162.213.33.250:443/api"
16:59:23 DEBUG juju.api apiclient.go:590 dialing "wss://162.213.33.28:443/api"
16:59:24 DEBUG juju.api apiclient.go:603 error dialing websocket (certificate error true): websocket.Dial wss://162.213.33.250:443/api: x509: cannot validate certificate for 162.213.33.250 because it doesn't contain any IP SANs
16:59:24 DEBUG juju.api apiclient.go:603 error dialing websocket (certificate error true): websocket.Dial wss://162.213.33.28:443/api: x509: cannot validate certificate for 162.213.33.28 because it doesn't contain any IP SANs
16:59:24 DEBUG juju.api apiclient.go:593 successfully dialed "wss://jimm.jujucharms.com:443/api"
16:59:24 INFO juju.api apiclient.go:521 connection established to "wss://jimm.jujucharms.com:443/api"
16:59:25 DEBUG juju.juju api.go:263 API hostnames unchanged - not resolving
16:59:25 DEBUG juju.api monitor.go:35 RPC connection died