Full Error: URL Blocked: This redirect failed because the redirect URI is not whitelisted in the app’s Client OAuth Settings. Make sure Client and Web OAuth Login are on and add all your app domains as Valid OAuth Redirect URIs.
This is a redirect URL problem. Facebook automatically generates a redirect URL which is http://...[your domain]..../signin-facebook. You need to add this URL to Client OAuth Settings along with your own redirect_URL like below: 
If Punchh manages your iFrame, please reach out to support.punchh.com for further assistance. If your own team takes care of your iFrame, this will be a request for your internal team.