How to watch “Owner has not made this video available on mobile” videos
If you are a frequent youtube user you might have come across a video that isn’t enabled on mobile. Youtube allows creators to enable or disable the ability to watch the video on mobile devices, this is mainly done for ad revenue and copyright content (which both work different on mobile then on desktop).
Watch “Owner has not made this video available on mobile” videos on Android
There are several workarounds that work on Android that don’t require too much work, the easiest one is using the Opera web browser, the Opera browser is great for this occasion because it allows us to change the type of browser we want to use, either appear as a mobile device or desktop (this means all website will load a mobile version or desktop version) this is also handy for Youtube as it will appear like a desktop computer and doesn’t apply the “available on mobile only”
Watch “Owner has not made this video available on mobile” videos on iOS
On iOS it is even easier then on Android. Apple knows this issue annoys a lot of users and that is why it has modified Safari to do essentially the same thing as Opera. Whenever a video isn’t available on Mobile, Safari will automatically load the desktop version of youtube allowing you to watch the video without any issues (source)