Why am I experiencing a function activation error on Shopify?

[Radixsecur1ty]

Hello Guys,

I have just created my first shopify function based on the official tutorial.

I have a development store with checkout customization enabled.

I have deployed my function successfully.

However when i want to activate it with the following query, i receive an error:

mutation {
checkoutServerExtensionCreate(input: {
functionId: "YOUR_FUNCTION_ID_HERE"
}) {
checkoutServerExtension {
id
}
userErrors {
message
}
}
}

{
"data": {
"checkoutServerExtensionCreate": {
"checkoutServerExtension": null,
"userErrors": [
{
"message": "The function provided is not valid to be used as a checkout server extension."
}
]
}
}
}