API result is different than the dashboar

https://api.cloudflare.com/client/v4/Zone-Identifier/analytics/dashboard?since=2019-05-23T19:10:00Z&until=2019-05-23T19:39:00Z

I got the results within the given time frame. However, the result is different than the cloudflare dashboard.

For instance I want to see last 30 minutes Unique Visitors or Requests under Analytics and expecting the matching result as the CF Dashboard.

Please advise!

Thanks,

Open a support ticket in this case.