by Daniel Palou.
Thanks for the credentials,
this isn't an iOS9 issue, it fails in Android too. I've opened an issue about this:
https://tracker.moodle.org/browse/MOBILE-1237
The problem is that a server call takes too long to respond. In the next release we'll increase the timeout value of this call. With this increased value I can access in your site but it takes a while to do so.
This call to login/token.php is taking 23 seconds to respond, that's not normal. Your admin should verify why is it taking that long.
Regards,
Dani