Error: The response content type 'text/html; charset=iso-8859-1' isn't the expected XML

Something bad happened during the deployment because the engine complains about an host not included in the cluster:

2018-07-05 21:34:47,768-04 WARN  [org.ovirt.engine.core.vdsbroker.gluster.GlusterVolumesListReturn] (DefaultQuartzScheduler6) [3009952a] Could not add brick 'lago-hc-basic-suite-4-2-host1:/rhs/brick1/engine' to volume 'c1146520-3bf7-4b81-b31a-7cc5475b6438' - server uuid '50e37ed8-86f3-4b50-9258-f516169025ea' not found in cluster '3125aa60-80bb-11e8-a143-00163e24d363'

Sahina, Gobinda, can you please investigate?

Ondra, no idea why the engine is returning text/html instead of xml here, can you please check?