I got it to work finally but only when I actually published it as alpha and installed it from google play. I am quite sure that my problem was that I haven't done the preview access authorize right. On Scirra's help site about the Google Play plugin there is some info on how to do this, but I feel like there have been some changes, can't follow along and find the settings.
Somewhere deep in the API settings I found some similar options to change, see post before.
From - construct.net/en/make-games/manuals/construct-3/plugin-reference/google-play
ENABLING ACCESS IN PREVIEW MODE
When testing your project, your game will run from preview.construct.net/local. Since this is is different to the published URL of your game, Google Play Game Services will block access unless you add the preview URL as a permitted location.
To do this, in the Developer Console under Game details, find the header that says API CONSOLE PROJECT and follow the link to the API console project for your game. In the API console, select APIs & auth, then Credentials. Notice the Javascript Origins field contains only your final URL; this also needs to contain any preview URLs to be allowed access. Click Edit settings. Under Authorized Javascript Origins, make sure the final URL and the preview URL appear on separate lines.
mywebsite.com/games/myawesomegame
preview.construct.net/local
Click Update. Now your game should be authorised to be accessed from preview mode as well as when you publish it.