Invalid Cron Expression

refresh: Invalid cron expression '{expression}': {detail}

{
  "defaults": {
    "enabled_stats": ["value_count"]
  },
  "refresh": {
    "trigger": "cron",
    "cron_expression": "not a cron"
  }
}

┌───────────── minute (0–59)
│ ┌───────────── hour (0–23)
│ │ ┌───────────── day of month (1–31)
│ │ │ ┌───────────── month (1–12)
│ │ │ │ ┌───────────── day of week (0–7, 0 and 7 = Sunday)
│ │ │ │ │
* * * * *

{
  "defaults": {
    "enabled_stats": ["value_count"]
  },
  "refresh": {
    "trigger": "cron",
    "cron_expression": "0 0 * * *"
  }
}