Stream data rejected during Elasticsearch load


We have configured the speed layer for stream enrichment. The data is being indexed to Amazon elasticsearch perfectly for all the events from good kinesis stream. But one of the events data is not being indexed and getting rejected to rejected kinesis stream. The format for the particular attribute of the event is :

Can you please help us with the solution to handle and index this kind of particular events data. Also help me understand why this event is going to rejected kinesis stream after enrichment.

Thank you.