HTTP GET request returns all submissions even when search field id and value is provided

curl --request GET
--url 'https://www.formstack.com/api/v2/form/xxxxxxx/submission.json?search_field_x=xxxxxx&search_value_x=xxxxxxxxx.ca&data=false&expand_data=false'
--header 'X-FS-ENCRYPTION-PASSWORD: xxxxxxxx'
--header 'accept: application/json'
--header 'authorization: Bearer xxxxxxxxxxxxxxxxxxxxxxxxxx'

I am using search field ID and search field value in the API call but it returns all the submissions. The way i am using it is as below example where search field id is the JSON field id of the form textbox

search_field_x= 111111111

search_value_x=[email protected]