FDo you run the login as is? or did you fork it and change some things? I tested it with the "deploy to vercel" button, where the login was deployed, and i had to add the domain of my instance, the user id and token of a service user, with only that 3 env vars it worked fine. I asume that should be the same if you run it locally
Fhow did you configure everything?
Fso you have to add the domain where your login is running to the trusted domains of your instance
Fthen your app needs to point towards that login ui