Fess: No search result with Elasticsearch

(from github.com/vikasruhela)
I am using fess 13.1 with elasticsearch 7.1.1. I am able to create the connection and i can see the elasticsearch indices in Fess Admin Dashboard. However, whenever i search something on fess it shows no results.
Please let me know any steps to make the search possible. I have installed all the required plugins.


(from github.com/marevol)
Did you check log files?

(from github.com/vikasruhela)
I am not getting any error in fess-crawler.log.

(from github.com/marevol)
How many indexed documents are there in fess.yyyymmdd index?

(from github.com/vikasruhela)
Zero.

(from github.com/marevol)
Is your crawling configuration correct?