hi @filip.debacker and thanks for reaching out to Auth0 Support!
Sounds like that error is related to your Authorization code flow not working as expected, here’s a list of our event type codes which may be useful.
You mentioned having an Angular application, is it modeled in Auth0 as a SPA or Regular Web Application (RWA)? For front end applications like that we recommend it being a SPA, in which case the Auth Code Flow is not recommended and should use the Implicit Flow, more on that here:
Please review those materials and if you’re still facing issues, could you please send me your tenant in a DM and I can review your setup further.