There is no data except for last hour in WSO2 EI Analytics

Question

I'm using WSO2 EI 6.1.1. I have followed the steps in this article. But I can only see the statistics for the last hour, but not for last 24 hours, last 30 days, last year, nor any custom range.

WSO2 EI Analytics for last hour and last 24 hours respcetively