I cannot embed videos from cloudflare stream to my wordpress site

I’ve just started to use cloudflare’s stream. I’ve uploaded a video but when i embed it my website, it starts to go black time to time. Sometimes it seems okay but then it goes again. Also embed code really does not shows the thumbnail image. And if u look closely to the image, you can see the white line under the video. That is the video playing on background. I tried to paste the link to my theme but it gives me this error:" No compatible source was found for this media." Also i’ve tried accessing from another device, browser, location via vpn.