WebRTC screen capture is still unsafe even if HTTPS is used

I'm trying to catch the screen and display it in the browser (Mozilla Firefox). For that purpose I use WebRTC and web-server. HTML and JS are here:

$(document).ready(function() {

    screen_constraints = { 
        video: {
          mediaSource: "screen"
        }   
    };

    navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || window.navigator.mozGetUserMedia || navigator.msGetUserMedia;
    window.URL = window.URL || window.webkitURL;
    navigator.getUserMedia(screen_constraints, onstream, onerror);

    function onstream(stream) {

        var video = document.querySelector('video');
        video.src = window.URL.createObjectURL(stream);
        video.play();
    }

    function onerror(e) {

      console.error(e); 
    }
});

<!DOCTYPE html>
<head>
<script type="text/javascript" src="jquery-2.1.4.js"></script>
<script type="text/javascript" src="scripts.js"></script>
</head>
<body>

        <video autoplay></video>

</body>
</html>

But after executing this code the error occurs and console shows:

MediaStreamError { name: "SecurityError", message: "The operation is insecure.", constraint: "", stack: "" }

The console also shows the warning before error: "This site uses the SHA-1 certificate; it is recommended to use certificates with the signature algorithms that use stronger hash than SHA-1.". I'm using HTTPS, and I've added my site to the exceptions list of my browser and allowed all permissions for it, but this error occurs constantly :(
Please, help me to resolve this problem!

Solution

Probably this is because of same origin issue. Make sure the flags are set correctly in about:config,

make sure media.getusermedia.screensharing.enabled is set true
and the media.getusermedia.screensharing.allowed_domains list contains your domain name( including the www. if it is that way in your certs),
and as for the This site uses the SHA-1 certificate;... warning, you can ignore it, it does not affect screen sharing.