Thanks guys, for my case, Google Play Game Service and Google Play Game Management were enabled when I enable Google Play Game Service. So I have to enable Drive API manually. Thanks!
Thanks guys, I’ve tried one whole day in order to solve this error 8 problem, before I found this link.
@Lerg you have to specify this for your updated doc.
enable Drive API manually
Sorry to bump an old topic but many many thanks for @weshwf for his solution. I was at wits end trying to get the Android leaderboard and achievements to work under the new GPGS plugin. After I enabled Drive API and Google Play Developers API, they both finally worked.
I second the motion of having this added into the GPGS documentations, at the very least some kind of a note to let devs know that this is a possible fix.
Cheers 
having this added into the GPGS documentations, at the very least some kind of a note to let devs know that this is a possible fix.
That’s an excellent idea. Should be part of the standard implementation checklist for GPGS and surely it will be soon.
As a side note, this issue results from the error handling on Google’s part. Returning “Internal error” doesn’t say anything about what’s wrong. It should definitely be more specific. It’s like the Corona simulator just said “there’s an error somewhere in your code” without giving any specifics.
Got into the same issue when transferring from the old system to the new GPGS plug-in. Should have been detailed in the docs. too much overhead and time lost with no leads just to rebuild under the new system.
Hi;
I am doing the same thing as rune7 today (updating older games to new gpgs).
weshwf — you deserve the “Genius-of-the-Day” award. How you figured out the dependency on Google Drive API is beyond me! Thanks so much. As a result of this thread, I only wasted an hour or so on this problem rather than a far longer period. Kudos.
And yes, this needs to be detailed carefully in the docs.
Steve
I also want to thank everybody in this post, for me it was the
Drive API
that was missing. (Google Play Game Services was already enabled)
The Google Play Android Developer API is still disabled in my case.
I already could do the login and got the player details. I did, however, not test the leaderboards or other stuff jet…
Note that it took some few minutes after enabling the API until I got the login working. Now rebuild was necessary.
@corona staff, please update the documentation with this information.
Best,
Felix
Agreed, we need to add this. I’ve asked for the docs to be updated.
As an FYI at the bottom of each documentation page is a link to report issues with the docs. This gets into our ticketing system and assigned to the documentation team. Kinda like bugs, it’s better to track them in the ticketing system and make sure they get assigned rather than depend on the forums for that.
Rob
I have a question for those who experienced this error. Are you using Saved Games?
We are trying to determine if this Drive API is required for everyone, or only for Saved Games users, which is what Google seems to imply.
Thanks
Rob
Saved Games is not enabled for me.
We’re not using saved games.
Me neither. I was only trying to log the user in.
I do not use saved games neither, only leaderboards for now.
Hi Rob;
My app didn’t used “saved games” either. It simply has leaderboards and achievements.
Steve
Okay, thanks everyone! We are working to get to the bottom of it. For now we know the work around is to enable the Drive API even if you’re not planning on using snapshots.
Rob
Thank you so much guys! :) Had been debugging this for hours before I found this thread. Enabling Drive API was all that was needed to make it work for me as well. Wish that information had been part of the docs or otherwise made more obvious.
I got exactly the same problem 
I had this issue before and the problem was I hadn’t created at least 5 achievements.
Legacy plugin uses an outdated GPGS SDK version, it could be more permissive than the newer one.
Is your Game Services app a newly created one or is it something that is already used for some time? E.g. with real users data?
In my case its a newly created one, however Im not new to getting GPGS working and from what I can see everything is set up as it should be.