Chrome Vimeo Iframe autoplay not working anymore

yes, according to their documentation it is.

https://help.vimeo.com/hc/en-us/articles/115004485728-Autoplaying-and-looping-embedded-videos

EDIT:

Advance browsers like FireFox, Chrome and Safari are now blocking video autoplay by default.

CHROME Auto-Play Policy:

https://developers.google.com/web/updates/2017/09/autoplay-policy-changes

The Media Engagement Index, or MEI for short, a way of Chrome is to allow AutoPlay audio on your page to be based on your previous interactions with this webpage as a user. You can see what this looks like by going to

chrome://media-engagement/

MEI is calculated per user profile, and is persisted to incognito mode.

WEBKIT/SAFARI Auto-Play Policy:

https://webkit.org/blog/7734/auto-play-policy-changes-for-macos/

FIREFOX Auto-Play Improvements:

https://www.ghacks.net/2018/09/21/firefox-improved-autoplay-blocking/

NOTE: Don’t assume a media element will play, and don’t show the pause button from the start. Look at the Promise returned by the play function on HTMLMediaElement to see if it was rejected:

var promise = document.querySelector('video').play();

if (promise !== undefined) {
    promise.catch(error => {
        // Auto-play was prevented
        // Show a UI element to let the user manually start playback
    }).then(() => {
        // Auto-play started
    });
}