Error 503 Backend fetch failed Guru Meditation: XID: 118217200 Varnish cache server

A 503 error means that the webserver trying to be reached is unavailable overloaded, down for maintenance, or not fully functional for another reason. First, test the website directly from the webserver, and if it is running correctly then the problem is on the Varnish side and you should check varnishlog

varnishlog -g request -q 'RespStatus == 503'

If you see "FetchError c no backend connection." errors check the port and address of the server Varnish is trying to connect to. If your back-end is running but Varnish Cache is serving 503 then this is most likely due to the timeouts. To fix this, disable the keep-alive option and Varnish will drop idle connections.

  "origin": {
       "address": "origin.example.com",
       "disable_keepalive": true
   }