Michal,
Go to your url for your stream service: https://mirie-pc.stltd.co.il/arcgis/rest/services/cars_Feed/StreamServer
At the bottom where it says Web Socket URLs, copy "ws://yourserver:6180" -- I assume "ws://mirie-pc.stltd.co.il:6180."
Depending on your security method (https only or http/https), you might have to grab "wss://" or "ws://". I would try "ws://" first.
Log into your arcgis server admin https://hostname:6443/arcgis/admin -- https://mirie-pc.stltd.co.il:6443/arcgis/admin
Go to System-> Properties
Update your server properties with this format:
{"WebSocketContextURL": "ws://yourserver:6180"}
or if the url is correct from above:
{"WebSocketContextURL": "ws://mirie-pc.stltd.co.il:6180"}
Hit update.
Let me know if that works for you, I had a similar issue on an amazon server and that fixed it for me.
~Alex