Oauth authentication always failing

Hi guys,
I have a peculiar problem with linking my Google assistant project to home assistant.
When trying to link the apps I get to this screen:

Nothing happens however long I wait. I can log in as normal using the “home assistant local” provider when accessing the gui normally. Only oauth requests gives me this. I’m on hassio, so adding debugging statements to the correct parts of the code is hard.

Where should I start to debug this?