Cors issues when start the login progress


we are new to Auth0 and try to connect our application to Auth0 at the moment.
Out local setup is a spring boot application in backend and a angular application in frontend. Our Angular application is built by webpack and owns a devServer that proxy to our backend port.

We followed the default spring boot setup and after opening our application we get a cors error, when trying to call: is available for purchase -
This Adress was forwarded by the spring boot oauth2 provider. When we call a backend api call directly we get a successful redirect to our page.

We tried several things to bring our cors configuration to work, but all the time the blocked cors comes from Auth0. Is there any setting to bring this up to running or any debug possibility why this fails?

We use the Universal Login page with nearly only default settings.