Help with Custom Token API

I am having trouble connecting to an API using the Oauth2 Custom Token method.

I have successfully connected to this API using Bubble’s ‘None or Self Handled’ method. Here I made the access_token GET call to save the Bearer token, and then manually entered the Token for future calls. The issue here is that the Token expires, so I need to use Bubble’s built in Custom Token method for the automatic token refresh. The issue is that when I try and setup the method using this, and when I try to make my first call, I get this error

This makes me think there is some error in Bubble’s behind the scenes calls to the service to get the Bearer Token. Has anyone seen this error before or have any idea why the calls might not be working?
Open to any ideas!

Here is the setup of the API Custom Token setup:

Here is the setup of the self handled GET call where I successfully have gotten the Bearer Token:

NOTE Just realized that the Bearer Access Tokens are supposed to be generated using a GET call, but the Custom Token Authentication type through Bubble makes a POST call - hence the error I received. Is there a way to use the Authentication “OAuth2 Custom Token” with a GET call instead of POST @emmanuel ?

Thanks

Having a similar problem. Surprised it hasn’t been resolved in nearly 4yrs.