Hello,
FB request gives the following https://gyazo.com/7c17d9f739a826ac52ffd1215895cae3
Looks that either you have any IP blocks in the FB settings or FB blocked your IP.
Read these posts and follow the solutions described there:
https://forum.bubble.io/t/solved-facebook-plugin-ip-cant-make-requests-for-that-application/9567
https://stackoverflow.com/questions/12072720/oauth-error-this-ip-cant-make-requests-for-that-application
Regards