YouTube Video autoplay

I am using a YouTube embed on my site. To make it autoplay I have added ?autoplay=1 to the embed too. The code when added to the page/post editor, is showing the video with autoplay. But on the front end, the video is not playing automatically.

Is there any possible reason for that?

Here is the code I am using:

iframe width="460" height="220" src="https://www.youtube.com/embed/rUWxSEwctFU?autoplay=1controls=0loop=1playlist=rUWxSEwctFUamp;showinfo=0" frameborder="0" allowfullscreen allow="autoplay"/iframe

Can anyone please let me know what I am doing wrong here?

Thank you in advance.

Update: I think it is working on Chrome, but not in Firefox