Google Cloud - oauth2client.client.HttpAccessTokenRefreshError: invalid_grant
<p>I got this error message when trying to execute Google Prediction API.</p>

<pre><code>raise HttpAccessTokenRefreshError(error_msg, status=resp.status)
oauth2client.client.HttpAccessTokenRefreshError: invalid_grant
</code></pre>

<p>My credential details</p>

<pre><code>{
    "scopes": [],
    "private_key": "XXXXX",
    "id_token": null,
    "token_uri": "https://accounts.google.com/o/oauth2/token",
    "token_info_uri": null,
    "token_response": null,
    "client_id": null,
    "scope": "https://www.googleapis.com/auth/prediction https://www.googleapis.com/auth/devstorage.read_only",
    "token_expiry": null,
    "_class": "SignedJwtAssertionCredentials",
    "refresh_token": null,
    "_module": "oauth2client.client",
    "private_key_password": "notasecret",
    "access_token": null,
    "service_account_name": "account-1@myapp-1136.iam.gserviceaccount.com",
    "invalid": false,
    "assertion_type": null,
    "kwargs": {},
    "client_secret": null,
    "revoke_uri": "https://accounts.google.com/o/oauth2/revoke",
    "user_agent": null
}
</code></pre>