Error: Invalid OAuth2 redirect_uri

I have been trying to integrate Discord as a Provider in an Application that uses Strapi v3. Despite following the guide specified on the website (Documentation) I wasn’t able to reach my goal: Authenticate users in Strapi via Discord.

After many attempts, I have encountered the following error repeatedly and couldn’t conclude if it is an error due to new updates or if I am doing anything wrong.

Thanks for your time and hope to receive your help! ; )