SearchContextMissingException

Hi,
am using ES 16.0. while searching with child query and search type as dfs_query_then_fetch.
i have got below error.

{"took":407125,"timed_out":false,"_shards":{"total":6,"successful":2,"failed":4,"failures":[{"reason":"RemoteTransportException[[Omega the Unknown][inet[/10.41.23.16:9300]][search/phase/fetch/id]]; nested: SearchContextMissingException[No search context found for id [9998]]; "},{"reason":"RemoteTransportException[[Ebon Seeker][inet[/10.41.23.19:9300]][search/phase/fetch/id]]; nested: SearchContextMissingException[No search context found for id [7908]]; "},{"reason":"RemoteTransportException[[Ebon Seeker][inet[/10.41.23.19:9300]][search/phase/fetch/id]]; nested: SearchContextMissingException[No search context found for id [7909]]; "},{"reason":"RemoteTransportException[[Sweetface][inet[/10.41.23.21:9300]][search/phase/fetch/id]]; nested: SearchContextMissingException[No search context found for id [5086]]; "}]}

Pls help to move forword.