Xano Oauth not working.

I've been following precisely the guide on how to setup custom backend on Bravo step by step and I've also watched some video tutorials on the topic.
Still there are certain aspects not covered enough and I'm not able to login through my app.
I'll go through each aspect of the Login-authentication, so you can check with me if it was done properly

-1 **API collection settings
**Under the collection settings, I selected Bearer token and then I didn't write down any Bearer token

-2 Integrations 

1. I enabled custom login 
2. I selected Xano  
3. I selected an endpoint collection and I have chosen the ME endpoint, that is the endpoint that Xano autogenerates to retrieve info about the authenticated user 
4. I have changed the data name accordingly to how it was required

-3 Login API request 

1. have added some test values to the request and I have verified that it works

-4 Data binding 

1. connected email and password fields so that input is added to the fields ${email} and ${password} of the request 
2. The sign-in button is not bonded to any API collection, on Figma the element is tagged [action:login] 
3. I have selected as "set access token" if the action is on success

+++Right now I get error 500++

**Additional very strange things happening
**
I have an endpoint PUT-user that modifies user details, it is an authenticated method and:
it works as long as I keep on the collection settings (under section Authentication)  "none" field selected. As I select Bearer token it stops working.

If you have any idea on what I could do, even if you are not sure, please let me know, at this point I don't know what else to do!