We have all our course videos on Vimeo, set to a private link.
Up until now pasting the plain link has worked, even for private videos, but Vimeo have changed the settings and only embed video links will work:
They recommend we post the full embed: (I know the video won’t show as this domain is not specified), but this does not even show it is a video on our posts… ??
I just started having the problem as well, it seems they are not allowing embeds of private videos anymore. If you change your security settings of the video to hidden from vimeo and ensure your domain is listed under the embed section it should fix the problem.
The reason why the Vimeo link added with privacy hash isn’t working completely depends upon the hosting platform as well as website builder because some could strip off the hash code even though you embed it correctly.