Filter is not working on WebHierarchicalDataGrid


We are using Infragistics4.Web.v14.1 and implemented the WebHierarchicalDataGrid in our project.When we filter  on large amount of data, "Async request failed"  error occured.So we tried a free trail of infragistics new version 18.1.20181.23.Then also same issue occured and also filter is not working for data source having empty strings.What's the solution for this.

Looking forward for your reply.