Backend error 500 when accessing Chrome Web Store licensing API

Question

I'm trying to make a chrome extension, which will have a free trial. Following the documentation here, the first thing to do is enabling Chrome Identity API. As far as i can tell, there's no such thing...

Anyway... I've done every other steps, and ends up with a 500 error.

Here is part of what i've done. Of course i changed values of all ids, keys, token, etc..

manifest.json

    {
      "name": "The name of my app",
      "version": "1.0.9",
      "key": "my_very_long_key",
      "description": "A description",
      "manifest_version": 2,
      "permissions": [ "activeTab", "storage", "declarativeContent", "identity", "https://www.googleapis.com/" ],
      "oauth2": {
        "client_id": "the_client_id_i_setup_in_Credentials_oauth2_section.apps.googleusercontent.com",
        "scopes": [
          "https://www.googleapis.com/auth/chromewebstore.readonly"
        ]
      },
    // other stuff...

code

chrome.identity.getAuthToken({
  'interactive': true
}, (token) => {
  console.log("Token: %o", token);
  console.log("chrome.runtime.id: %o", chrome.runtime.id);

  var CWS_LICENSE_API_URL = 'https://www.googleapis.com/chromewebstore/v1.1/userlicenses/';
  var req = new XMLHttpRequest();
  req.open('GET', CWS_LICENSE_API_URL + chrome.runtime.id);
  req.setRequestHeader('Authorization', 'Bearer ' + token);
  req.setRequestHeader('Content-Type', 'application/json');

  req.onreadystatechange = () => {
    if (req.readyState == 4) {
      var license = JSON.parse(req.responseText);
      console.log(license);
    }
  }
  req.send();
});

And here is an example of output.

Token: "ya29.GlzqBp1FaFegsgm.oihohjbrbznghdfgmgighnzxfvxz3ve5G8GQ4VxZ653FqBa8aqq-JXil-VS5IGeknneZ6KnKbyknw-gXw"
chrome.runtime.id: "asdflhlkrfhuilerdfb"

Object
    error:
        code: 500
        errors: Array(1)
            0:
                domain: "global"
                message: "Backend Error"
                reason: "backendError"
                __proto__: Object
            length: 1
            __proto__: Array(0)
        message: "Backend Error"
        __proto__: Object
    __proto__: Object

So i'm able to obtain the access token, but then calling the API with it doesn't seem to lead to anything.

Answer 1

Reopened bug: https://issuetracker.google.com/issues/140188619

Please, star it on issuetracker.google.com, if you have the same issue to speed up Google)

UPDATE:

Issue was fixed by Google! https://bugs.chromium.org/p/chromium/issues/detail?id=940478#c18