It does not work "Stop Word"

Elastic Stack Elasticsearch
1

Hello!

It does not work "Stop Word"

I have this mapping:

fos_elastica:
clients:
default: {host: localhost, port: 9200}
indexes:
website:
settings:
index:
analysis:
analyzer:
my_analyzer:
language: english
tokenizer: nonutf8letter
filter: [standard, lowercase, asciifolding, stop, custom_stop]
tokenizer:
nonutf8letter:
type: pattern
pattern: '[^ \ pL \ pM \ p {Nd} \ p {Nl} \ p {Pc} [\ p {InEnclosedAlphanumerics} && \ p {So}]]'
filter:
custom_stop:
type: length
min: 3
max: 2000
types:
deals:
mappings:
id: boost {3}
nombreoa {analyzer: my_analyzer}
idareaestudio:
type: "nested"
properties:
name: {type: String, index: not_analyzed}

When i search "a" brings me everything and want to exclude me the words of 1 or 2 letters.

Any idea what I do wrong?