[iPad][Configurator 2] Safari can't play MP3's. "because it is restricted."

[Garacesh]

Our school have signed up with some online literacy assessment website and the tests involve questions like "Apple iPads ______ me.", with a little 'Play' button that plays an mp3 file of the spoken sentence ("Apple iPads annoy me. Spell Annoy.")

 

This works fine on our Windows desktops. However on the iPads we get "You cannot browse this page at "literacyassessment.co.uk" because it is restricted."

I've checked Smoothwall and it's not logging the request at all (whereas it does on Windows boxes - and HTTP 200's it) so that leads me to believe the problem lies somewhere with the supervised settings. Trouble is, I can't see anything in Configurator's settings that restrict it.

 

Anyone hit this snag before?

[Brimstone]

First thing I would do is get a test iPad and unsupervised it to test, could possibly be the trust cert being used in Configurator?