Dimension does not execute in explore

[mohiit_jain3]

I have:

dimension: fl {
    type: string
    sql: CONCAT('flt-', ${departure_date}, '_' , ${oa.iata}, '-', ${da.iata}) ;;
    }

  dimension_group: departure {
    type: time
    timeframes: [
      raw,
      time,
      date,
      week,
      month,
      quarter,
      year
    ]
    sql: TIMESTAMP (${TABLE}.departure_at, “UTC”) ;;
  }

But its throwing this error in Looker when I am creating a dashboard in an explore--

 

The Google BigQuery Standard SQL database encountered an error while running this query.

Query execution failed: - Syntax error: Illegal input character "\342" at [2:56]

SELECT    CONCAT('flt-', (DATE(TIMESTAMP (legs.departure_at, “UTC”) , 'America/Los_Angeles')), '_' , oa.iata, '-', da.iata)  AS fl

However, this perfectly works when I run this as a sql query. I don’t understand the reason why? can anyone please help?