Update: These seems to be asked on Meta.Se as Please Improve supported URLs list for Embedded YouTube videos. It has very little support. I posted the below as an answer to try to improve views for the question. Please upvote it so that it gets some traction.
Sometimes youtube urls arnt parsed if it doesn't fit a specific format. Can we request that it be expanded?
Please add
Mobile links with the "m." subdomain
- https ex:
https://m.youtube.com/watch?v=71fWtJXEI0Q
- http
ex:
http://m.youtube.com/watch?v=71fWtJXEI0Q
No Subdomain
- https ex:
https://youtube.com/watch?v=71fWtJXEI0Q
- http ex:
http://youtube.com/watch?v=71fWtJXEI0Q
Shortened by youtube's shortener
- https ex:
https://youtu.be/rEWaqUVac3M
Per a related question, Supported URLs for video embedding the current supported ones are:
http://youtu.be/rEWaqUVac3M http://www.youtube.com/watch?v=rEWaqUVac3M https://www.youtube.com/watch?v=rEWaqUVac3M
While some unsupported ones are:
https://youtu.be/rEWaqUVac3M http://youtube.com/watch?v=rEWaqUVac3M https://youtube.com/watch?v=rEWaqUVac3M
https
.