Filebeat throwing mapper_parsing_exception

I am sending filebeat output to elastic search. In filebeat logs, can see mapper parser error. trying to load dynamic template manually (through postman) but still getting error. filebeat is on K8S cluster and ES is hosted on cloud.
Here is the filbeat required config and dynamic template.

Prospectors:
- type: log
paths:
- /var/lib/docker/containers//.log
- /var/data/kubeletlogs///*.log#
json.message_key: log
json.keys_under_root: true
logging.files.keepfiles: 7
fields:
clustername: {{ .Values.clustername }}

Processors:

processors:
- add_kubernetes_metadata:
in_cluster: true
- decode_json_fields:
fields: ["message"]
process_array: true
max_depth: 10

index: "app-log-6.5.4-%{+YYYY.MM.dd}"
setup.template:
  name: "max-log"
  pattern: "max-log-*"
  enabled: true
  fields: fields.yml
  overwrite: true

Dynamic template:

{
"template" : "app-*",
"order" : 1,
"settings" : {

},
"mappings": {
                                       "_default_": {
                                                      "dynamic_templates": [{
                                                                    "message_field": {
                                                                                  "path_match": "message",
                                                                                  "match_mapping_type": "string",
                                                                                  "mapping": {
                                                                                                 "type": "text",
                                                                                                 "norms": false
                                                                                  }
                                                                    }
                                                      }, {
                                                                    "string_fields": {
                                                                                  "match": "*",
                                                                                  "match_mapping_type": "string",
                                                                                  "mapping": {
                                                                                                 "type": "text",
                                                                                                 "norms": false,
                                                                                                 "fields": {
                                                                                                               "keyword": {
                                                                                                                             "type": "keyword",
                                                                                                                             "ignore_above": 256
                                                                                                               }
                                                                                                 }
                                                                                  }
                                                                    }
                                                      }],
                                                      "properties": {
                                                                    "@timestamp": {
                                                                                  "type": "date"
                                                                    },
                                                                    "@version": {
                                                                                  "type": "keyword"
                                                                    },
                                                                    "geoip": {
                                                                                  "dynamic": true,
                                                                                  "properties": {
                                                                                                 "ip": {
                                                                                                               "type": "ip"
                                                                                                 },
                                                                                                 "location": {
                                                                                                               "type": "geo_point"
                                                                                                 },
                                                                                                 "latitude": {
                                                                                                               "type": "half_float"
                                                                                                 },
                                                                                                 "longitude": {
                                                                                                               "type": "half_float"
                                                                                                 }
                                                                                  }
                                                                    }
                                                      }
                                       }
                         }

}

  1. Deleting indices from ES 2)loading template through postman (PUT req) 3) starting filebeat.

Error: {"type":"mapper_parsing_exception","reason":"failed to parse field [message] of type [text] in document with id 'sU9P4mwBlXscRF4xIyDU'","caused_by":{"type":"illegal_state_exception","reason":"Can't get text on a START_OBJECT at 1:191"}}

What mapping I am doing wrong/missing?

can someone pl look into it?