The problem is due to an issue with iOS 9.3.1 and vimeo.com privacy settings. We use Vimeo to host all of our videos and have certain privacy settings enabled to prevent viewing the subscriber only videos without a subscription. Unfortunately these settings seem to be having trouble with iOS 9.3.1.
If iOS 9.3.1 is what you are running on your iPhone or iPad, then the videos may have issues with playback on those devices.
Both Vimeo and Apple are aware of these issues. A fix is expected with the release of iOS 9.3.2, but unfortunately, there’s no ETA on this as Apple does not announce in advance when it will release these updates.
Until this fix comes, the videos can be viewed on your Mac. Sorry for the inconvenience!
Kind regards,
Christine