Since Keycloak version 17, they removed the /auth in every URLs, either to retrieve the authorization code or the token one.

The Keycloak documentation is available here Breaking Changes

In order to work, I believe in the KeycloakApi, we must change the getAccessTokenEndpoint() and getAuthorizationBaseUrl() to support having this <baseUrl>/realms/<realm> instead of the previous one <baseUrl>/auth/realms/<realm> when using Keycloak version 17 and more