Nikos Nikoloutsakos

Hi so my problem is not how to set the `token_uri` variable, but how to achieve the authentication via a proxy endpoint. So following the test code [here](https://github.com/googleapis/google-auth-library-python/blob/37141e4dffc2ba3f3f57c5914544fb8b9cf7d017/tests/oauth2/test_service_account.py#L47): i get...

actually yes, i have deployed my code on a node that has no internet access, but I can send requests via a proxy as I said (https://example.com/oauth2/token) that would forward...

For my case the workaround was to hard-code the payload url inside: `site-packages/google/oauth2/service_account.py` Just search for the `"aud": self._token_uri` and set the correct url, you will find it in two...