curl not working in El Capitan
The errors shown suggest that you installed curl (v7.48.0 or much older) via homebrew or with another custom installer. The system's own original curl (v7.43.0) is located at /usr/bin/. Additionally it seems that curl is not installed as keg-only. This means that the homebrew curl is soft-linked to /usr/local/.

You may either update and repair brew/curl, modify curl.cfg to reflect proper paths or modify your PATH variable.

Or use the full path to the original curl: /usr/bin/curl