@julian I've solved the problem. Thank you very much!
Unable to Embed YouTube Using Plugin
Installed NodeBB Youtube Embed Plugin (nodebb-plugin-youtube-embed) and activated it.
But still, the YT video is not embedded. Just showing the plain URL (link).
Is it a compatibility issue ..I'm on NodeBB 1.14.0-12.
Or do I need to go with any other plugin?
Any fix for it?
Try using this one instead (it works for me on latest NodeBB)