Having mapper_parsing_exception when creating elasticsearch index all in Fields - elasticsearch

Question

I'm creating a winston-elasticsearch logger usin Kibana, where I need to save all what is happen in the app (request, apis, ...).I used this( https://github.com/vanthome/winston-elasticsearch) I defined a json mapping template. Also a transformer.js file where I define a Transformer function to transform log data as provided by winston into a message structure which is more appropriate for indexing in ES.
then I use the winston-elasticsearch to create new Es instance:
exports.mappingTemplate = require('../../../index-template-mapping.json');
const TransportersElastic = new Elasticsearch({
index: 'soapserver',
level: 'info',
indexPrefix: 'logs',
transformer: transformer,
ensureMappingTemplate: true,
mappingTemplate: mappingTemplate,
flushInterval: 2000,
waitForActiveShards: 1,
handleExceptions: false,...
But I keep getting Elasticsearch index error of type: 'mapper_parsing_exception' reasons like : failed to parse field [fields.result.status] of type [text]'
illegal_argument_exception' reason : 'failed to parse field [fields.rows.tmcode] of type [long]'
Here transformer.js:
exports.mappingTemplate = require('../../../index-template-mapping.json');
exports.transformer = (logData) => {
const transformed = {};
transformed['#timestamp'] = new Date().toISOString();
transformed.source_host = os.hostname();
transformed.message = logData.message;
if (typeof transformed.message === 'object') {
transformed.message = JSON.stringify(transformed.message);
I need help, suggestion how to resolve those error and succeed the Mapping.
Here the index-mapping-template.json
{
"mapping": {
"_doc": {
"properties": {
"#timestamp": {
"type": "date"
},
"fields": {
"ignore_malformed": true,
"dynamic": "true",
"properties": {}
},
"message": {
"type": "text"
},
"severity": {
"type": "keyword"
}
}
}
}
}