I am unable to stream YouTube videos using the Apple iPhone or iPad via the ProxySG when authentication has been configured.
YouTube streaming video on the iPhone or iPad utilizes a built in application which has no capability to automatically send a credential or login prompt. However, there are several ways to enable functionality for the iPhone and iPad devices:
In transparent mode, change the origin-cookie redirect mode to an IP base authentication like Origin-IP-Redirect. That will enable functionality if authentication has been performed while initially browsing youtube.com (or other sites) via Safari.
In an explicit set up, you can use an authentication Proxy IP mode (if suitable), but still require the user to initially authenticate while browsing youtube.com (or other sites) prior to using the youtube streaming application.
The simplest option is to disable authentication when the user agent is using the iPhone (or iPad). This can be done via VPM by creating a new rule on top of the existing authentication rule in Web Authentication Layer or by installing the following CPL in local policy: