google translate API authorisation problem

Question

I am trying to translate some text using GCP translation service with REST api https://translation.googleapis.com/v3 I'm using API key auth method.

url and Body

https://translation.googleapis.com/v3/projects/my-translator-1122333:translateText?key=thisismykey
{
    "content": ["Hello"],
    "sourceLanguageCode": "en",
    "targetLanguageCode": "ru"
}

However I got

{
  "error": {
    "code": 401,
    "message": "Request is missing required authentication credential. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.",
    "status": "UNAUTHENTICATED"
  }
}

Could anyone explain me what is wrong I do? Thanks