Client certificate fails with "unsupported certificate purpose" from iPad, works in desktop browsers

[JoakimR]

Whitout any configuretion it's imposible to do much rather than refer you to
nginx.org documentation
http://nginx.org/en/docs/http/ngx_http_ssl_module.html

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,272444,272507#msg-272507