title: Google Speech API returns 403 PERMISSION_DENIED
body: <p>I have been using the Google Speech API to transcribe audio to text from my PHP app (using the Google Cloud PHP Client) for several months without any problem. But my calls have now started to return 403 errors with status "PERMISSION_DENIED" and message "The caller does not have permission".</p>
  
  <p>I'm using the Speech API together with Google Storage. I'm authenticating using a service account and sending my audio data to Storage. That's working, the file gets uploaded. So I understand - but I might be wrong? - that "the caller" does not have permission to then read to the audio data from Storage.</p>
  
  <p>I've been playing with permissions through the Google Console without success. I've read the docs but am quite confused. The service account I am using (I guess this is "the caller"?) has owner permissions on the project. And everything used to work fine, I haven't changed a thing.</p>
  
  <p>I'm not posting code because if I understand correctly my app code isn't the issue - it's rather my Google Cloud settings. I'd be grateful for any idea or clarifications of concepts!</p>
  
  <p>Thanks.</p>