Machine known by its old IP

Hi,

We've got a controller with HA enabled, deployed on Azure.
One of its machines was rebooted and got a new public IP from Azure.
Juju still has the old IP, generating various fails in its operations.

Unit in error: machine-2

From the logs on machine-0:

2019-02-18 12:21:24 WARNING juju.mongo open.go:160 mongodb connection failed, will retry: dial tcp 52.174.101.58:37017: i/o timeout
2019-02-18 12:21:24 WARNING juju.mongo open.go:160 mongodb connection failed, will retry: dial tcp 52.174.176.245:37017: i/o timeout
2019-02-18 12:21:24 WARNING juju.mongo open.go:160 mongodb connection failed, will retry: dial tcp 52.174.180.115:37017: i/o timeout

2019-02-18 12:21:56 ERROR juju.worker.dependency engine.go:632 "firewaller" manifold worker returned unexpected error: machine 0 not provisioned
2019-02-18 12:21:58 ERROR juju.worker.dependency engine.go:632 "firewaller" manifold worker returned unexpected error: cannot respond to units changes for "machine-0": instances not found

2019-02-18 12:23:43 ERROR juju.worker.dependency engine.go:632 "compute-provisioner" manifold worker returned unexpected error: failed to process updated machines: failed to get all instances from broker: autorest/Client#Do: Preparing request failed: StatusCode=0 -- Original Error: detecting auth URI: expected unauthorized error response, got 404: subscriptions.GroupClient#Get: Failure responding to request: StatusCode=404 -- Original Error: autorest/azure: Service returned an error. Status=404 Code="SubscriptionNotFound" Message="The subscription '[...]' could not be found."

This last line is repeated with 2 different subscription IDs, none of which match the juju credentials.

`juju show-model controller` shows that it's using the right credential.

Thanks.