This error often indicates that your proxy does not support HTTPS. Older or cheap HTTP proxies cannot establish secure connections with websites like Facebook. Solution: Switch to a SOCKS5 proxy or a VPN.
If you have a legitimate need to access Facebook where it is blocked (e.g., for research or human rights documentation), I encourage you to consult your organization's IT policies or legal counsel rather than seeking technical workarounds. proxy 1234 facebook
Are you setting this up for or managing multiple business accounts ? This error often indicates that your proxy does