Actions on Google, account linking with amazon

I've made an action-on-google and I'm trying to use account linking with amazon.

I've created a security profile on Amazon, and gotten the client Id and client secret.

I have the allowed origins as : https://accounts.google.com/

The allowed return urls as : https://oauth-redirect.googleusercontent.com/r/_______

with my project id at the end.

I've tried it with linking type as implicit and with authorization code.

I've got the authorization url as https://www.amazon.com/ap/oa

When I did it authorization code, I had the token URL as : https://api.amazon.com/auth/o2/token:

When I integrated from dialogflow, with google assistant I ticked sign in.

Now when I try to invoke my app, its just leaves and gives me the error below:

Not really sure how to deal with this, I've made a bunch of actions and skills before and I've not hit this problem before.

I've looked on stack overflow and in other places for a solution, and I've tried resetting my app and just having an empty app. I feel like I'm missing something.

I found the "bug". Turns out the simulator automatically fails if you are the owner of the project and try to test account linking.

I made a second account, which was a test account, opened it on a different browser(incognito works as well) and it worked exactly as expected. I got the link, I logged in and it worked fine.

Quite annoyed by this since I feel like this should really not be the case.