Public API Example not working

I'm trying this request which I copy-pasted from the documentation at https://docs.railway.app/reference/public-api
and changed only the project ID

curl -X "POST" "https://backboard.railway.app/graphql/v2" \
     -H 'Authorization: Bearer xxxx' \
     -H 'Content-Type: application/json' \
     -d $'{
  "query": "query project{project(id:\\"bd0ee04e-9a92-4db9-869c-760973cc109c\\"){id name plugins{edges{node{id name}}}environments{edges{node{id name}}}services{edges{node{id name deployments{id status}}}}}}",
  "variables": {}
}'

And the response is:

HTTP/1.1 400 Bad Request
Server: nginx/1.18.0
Date: Tue, 20 Dec 2022 11:22:31 GMT
Content-Type: application/json
Content-Length: 95
Connection: close
Vary: Origin
X-RateLimit-Limit: 1000
X-RateLimit-Remaining: 990
X-RateLimit-Reset: 2022-12-21T11:17:29.914Z

{"errors":[{"message":"Problem processing request"},{"message":"Problem processing request"}]}