If the clickhouse_operator password contains a # character, HTTP requests using basic auth fail with a parse error.
It appears the metrics-exporter is not properly percent/URL-encoding.
E0916 22:38:06.764842 1 connection.go:90] connect():FAILED Ping(http://clickhouse_operator:***@HOSTNAME:8123/). Err: parse "http://clickhouse_operator:cs": invalid port ":cs" after host
In this case the password started with cs#.