Why am I getting an error when trying to apply a manual discount at checkout?

Hello, i am getting this error on try apply a manual discount in a checkout, have some alternative for this?

Admin API - HTTP put on resource:

https://{MyDomain}.myshopify.com/admin/api/2022-07/checkouts/{checkoutId}.json

Body:

{
"checkout ": {
"applied_discount ": {
"amount ": “8.0990”,
"title ": "discount- test ",
"description ": "discount test ",
"value ": "80.99 ",
"value_type ": "fixed_amount ",
"non_applicable_reason ": null,
"applicable ": true,
"application_type ": “manual”
},
"token ": “My Checkout Id”
}
}

Error:

{
“errors”: “For access to web checkouts, contact support through your Partner Dashboard.”
}