That video is hilarious. “I can prove I’m not a sock because here’s my fiancée’s Facebook page.” 
At least that posts. Trying to edit results in the “can’t embed media items” error.
ETA: apparently it only works once. Trying to post a second video with the trailing slash in a thread also results in the “can’t embed media items” error.
The thread.
Test
Interesting.
So the https://youtu.be/[VidID]/ method works for a post but the post can’t then be edited.
But meanwhile the more traditional https://www.youtube.com/watch?v=[VidD] method won’t even post successfully much less edit.
Strangely, using the “youtu.be” form of the URL and appending a slash to it allowed me to make the post above, though I can’t edit it. I’m certain it didn’t work before. Will try again on another video.
The “youtu.be” URL with an appended slash worked twice in a row for me, and I’m certain that prior to today it didn’t work at all, because I remember seeing that suggestion and trying it.
I got it to work 3 times in a row in the test thread.
But there does appear to be some erraticness, i will do more tests.
Never mind.
Curiouser and curiouser !
I replaced the final forward slash with a backslash …
and was then able to go back and edit it !
Trying that again …
ETA: coming back to add this …
It works !
(I had to come back to this thread because the test thread complained when i tried
to have 4 consecutive posts in it - bastard !!)
You’re right, it is erratic and unpredictable. The youtu.be URL with forward slash has suddenly stopped working, even with the exact same video I just successfully posted a moment ago!
Will try with a backslash … ETA: no, that just results in a Onebox link, not a video.
damn… i hadn’t spotted that !
Testing:
Using “Share”
Using “Share” a second time
OK- that all seems to work. Let’s try queueing up the video to start in the middle:
So- there is something definitely broken. I had to add backslash to get all three to show, and the third is not queued, even though the URL say it should be.
I also couldn’t edit the post to add the note above. Even though it took the first time, adding a line of text at the end of the post gave me the Embed Media error.
Going to try editing a post with a single video embedded:
Nope, now it won’t embed the James Brown video above…Somethings broken.
When I go up and edit the post I made 4 hours ago (City tears down man’s Atlanta house…), what I see inside the post is
(https://www.youtube.com/watch?v=ct8KpaxKeY0)note the parentheses. Now let’s see what happens when I snag a YouTube URL and post it directly with opening and closing parentheses…