Hi @golaphazi , I experienced the same issue.
I provided the redirect URL and it’s used correctly if a user agrees to provide permission on the facebook auth page. But if a user clicks on “Cancel” on the facebook when asked for authorization, redirect goes to “/wp-json/wslu-social-login/type/facebook” with error payload. I guess the plugin just doesn’t handle the failure case.
Thank in advance, great job!
Maksym