Tell me more ×  I'm trying to use the new Android subscription
system from Google Play into my application (I already had in-
app billing working fine). I have successfully done the
subscription billing, but I now want to retrieve informations
about this subscription by using the google apis as indicated in
the android documentation (  I want my service to be able to do
the API call to retrieve these informations, but I have problems
with authentication (with oauth2). So far, this is what I do (in
my php service) :  require_once 'google-api-php-
client/src/apiClient.php'  const SERVICE_ACCOUNT_NAME = 'email
from services account access'; $key = 'content of my private key
retrieved from services account access';      $client = new
apiClient(); $cred = new
apiAssertionCredentials(SERVICE_ACCOUNT_NAME, array(''), $key);
$assertion = $cred->generateAssertion(); // This generate my
encrypted JWT  I then try to retrieve the access token with this
JWT object. The problem is that when I use the access token
given I got