Lowercase normalizer not working

Elastic Stack Elasticsearch
6 
 "fieldName
":{
                  "analyzer":null,
                  "boost":null,
                  "eagerGlobalOrdinals":null,
                  "fielddata":null,
                  "fielddataFrequencyFilter":null,
                  "index":null,
                  "indexOptions":null,
                  "indexPhrases":null,
                  "indexPrefixes":null,
                  "norms":null,
                  "positionIncrementGap":null,
                  "searchAnalyzer":null,
                  "searchQuoteAnalyzer":null,
                  "termVector":null,
                  "copyTo":null,
                  "fields":{
                     "keyword":{
                        "boost":null,
                        "eagerGlobalOrdinals":null,
                        "ignoreAbove":256,
                        "index":null,
                        "indexOptions":null,
                        "normalizer":null,
                        "norms":null,
                        "nullValue":null,
                        "splitQueriesOnWhitespace":null,
                        "docValues":null,
                        "copyTo":null,
                        "fields":null,
                        "similarity":null,
                        "store":null,
                        "meta":null
                     }
                  },

normalizer showing null even though have applied it