Querying elastic search data by query api

i am passing in the request body {"query":{"bool":{"must": {"match":{"LogEvent.logData.message":"aa"}}}}} but it is throwing 406 saying invalid inputs in elk 6.8 but it is working in 5.5 elk stack .. can anyone please look into it?

Could you provide a full recreation script as described in About the Elasticsearch category. It will help to better understand what you are doing. Please, try to keep the example as simple as possible.

A full reproduction script will help readers to understand, reproduce and if needed fix your problem. It will also most likely help to get a faster answer.