"Sorry this resource is not available by this method" Message

Could anyone explain what settings students have used that would generate the message 'Sorry, this resource is not available by this method'? They are using Xerte Bootstrap and 99% of the submissions I can access - but not this one. I'd like to know what advice I can give the student to change whatever settings they've used so I can actually see what they've done. It's not my browser (I've tried 3) Thanks in Advance

This is a rather generic message. Most of the time it indicates there is something off with access permissions, like trying to 'play' a Private project.