Like Ruben says, embedding YouTube videos works best when you link directly to the video or use any of the tools proved by YouTube for sharing their hosted videos.
Look at the URL you're using:
https://www.youtube.com/watch?v=Z3O6eivpTas&t=213sAnd then look at the URL that YouTube automatically creates when using their share buttons:
https://youtu.be/Z3O6eivpTas?t=213Was your URL custom/manually created?---
The YouTube REGEX within UBBT760 and newer detects more than 32 of the most common YouTube variations:
GROUP 1
https://www.youtube.com/watch?v=GbPxZ2biOQUhttp://www.youtube.com/watch?v=GbPxZ2biOQU//www.youtube.com/watch?v=GbPxZ2biOQU
www.youtube.com/watch?v=GbPxZ2biOQUhttps://youtube.com/watch?v=GbPxZ2biOQUhttp://youtube.com/watch?v=GbPxZ2biOQU//youtube.com/watch?v=GbPxZ2biOQU
youtube.com/watch?v=GbPxZ2biOQU
GROUP 2
https://m.youtube.com/watch?v=GbPxZ2biOQUhttp://m.youtube.com/watch?v=GbPxZ2biOQU//m.youtube.com/watch?v=GbPxZ2biOQU
m.youtube.com/watch?v=GbPxZ2biOQU
GROUP 3
https://www.youtube.com/v/GbPxZ2biOQU?fs=1&hl=en_UShttp://www.youtube.com/v/GbPxZ2biOQU?fs=1&hl=en_US//www.youtube.com/v/GbPxZ2biOQU?fs=1&hl=en_US
www.youtube.com/v/GbPxZ2biOQU?fs=1&hl=en_USyoutube.com/v/GbPxZ2biOQU?fs=1&hl=en_US
GROUP 4
https://www.youtube.com/embed/GbPxZ2biOQU?autoplay=1https://www.youtube.com/embed/GbPxZ2biOQUhttp://www.youtube.com/embed/GbPxZ2biOQU//www.youtube.com/embed/GbPxZ2biOQU
www.youtube.com/embed/GbPxZ2biOQUhttps://youtube.com/embed/GbPxZ2biOQUhttp://youtube.com/embed/GbPxZ2biOQU//youtube.com/embed/GbPxZ2biOQU
youtube.com/embed/GbPxZ2biOQU
GROUP 5
https://youtu.be/GbPxZ2biOQU?t=120https://youtu.be/GbPxZ2biOQUhttp://youtu.be/GbPxZ2biOQU//youtu.be/GbPxZ2biOQU
youtu.be/GbPxZ2biOQU
GROUP 6
https://www.youtube.com/InvisibleAdvertising?v=GbPxZ2biOQUNOTE: Embedding will not display inline when you link to a video playlist, since that is a playlist and not a video.