Configuring magento with varnish exported vcl error 502

[Woshka]

hello,

I have installed varnish on a production magento2.2.7 server

and configured varnish to listen on port 80 and the apache as backend on port 8080

I changed the configuration in backend to use varnish and exported the vcl

after I changed the current vcl with the exported vcl I got the 503 Error

Error 503 Backend fetch failed

Backend fetch failed

Guru Meditation:

XID: 32771

---

Varnish cache server

I tried these Documentation but no luck

https://devdocs.magento.com/guides/v2.3/config-guide/varnish/config-varnish.html

https://devdocs.magento.com/guides/v2.0/config-guide/varnish/tshoot-varnish-503.html

Please help me figuring this out

Thanks

[kgerasimov]

Paste here your varnish.vcl file.