Have you ever tried to use Client Authentication through Safari browser? I have, and it does not work. Well, sometimes it does. There are even some SecureKnowledge cases about it, like sk40327.
But with one of my customer using VSX and SSL encyption instead of plain HTTP you could authenticate through any browser but Safari. The issue was platform independent. iPad, Mac or even Windows, Safari could not authenticate, period.
A user gets the initial auth page and types in a username, but instead of password prompt on gets an empty error page.
I have opened a support case, and guess what? Here is the official answer, quoted for my support case:
"...after consulting with R&D, I can officially assure you that using Safari on client authentication with VSX R67 version is not supported.
The only officially supported browser when using client authentication is Internet Explorer.
This statement is relevant for all Check Point versions."
That said, I expect Check Point to make this statement publicly available as a new SK and/or part of the Release Notes.