Unable to perform Fuzzy search for search query template

Hello Team

I am trying to create search query template to allow fuzzy search to search even incomplete values from field, After following the elastic document tried to create search query but it is not working.

Using below query i am trying to search the value "my system" by giving incomplete query as "my syst" from field "testfield.searchable"

SOmewhow it is not working, can anyone advice where i m doing wrong

"query": {
"bool": {
"must": [
{
"query_string": {
"query": "my syst",
"default_field": "testfield.searchable",
"fuzziness": "AUTO"
}
}
]
}
}