SFSC connection request: 404 Not Found

[abmedinaMnst]

Hello,

I'm testing the connection from my sandbox (SFCC) to SFSC. I have followed the steps of configuring salesforce commerce cloud.

When I place an order, the service-cloud-conector executes the orderSync script and creates a POST request to send.
First, an authorization request is launched and returns a valid token. This token has a parameter "instance_url", and this url is used as the API endpoint for the POST order request:

https://my-space.my.salesforce.com/services/apexrest/Order/Placement

However, when the call to that service is executed it throw a 404 Error:
[{
"errorCode": "NOT_FOUND",
"message": "Could not find a match for URL"
}]

Can someone help me with this?
Thanks!