Issue:-

While adding a json data to the MongoDB collection, following error has been observed.

MONGODB_13 - Error serializing record: java.lang.UnsupportedOperationException: BSON Converter cannot convert java.util.ArrayList to BSON Document

Solution:- 

MongoDB atlas was reading the record as a list. As the JSON data was enclosed with the e].

We have to set the JSON Content to JSON array of objects at the Origin side.