Error 503 Backend fetch failed Varnish cache server

[sachinaror2435]

Hello Friends,

I set up varnish 5 on my server and i restarted apache, varnish, and reload daemon also.

But after installation, I am facing 503 Backend fetch failed error. And my website on a subdomain with a folder named as DEV eg: domain.com/DEV/

->>>>>>>>>>>

Error 503 Backend fetch failed

Backend fetch failed

Guru Meditation:
XID: 65567

Varnish cache server

->>>>>>>>>>>

I changed the header length and response size also but still the same error. 

-p http_resp_hdr_len=65536 \ -p http_resp_size=98304

Your help will be appreciated.

Thanks

[Sunil Patel]

Hlello @sachinaror2435 

first check is request reached on server.

put echo exit into index.php

if works then it is issue with content length

[Bhanu Periwal]

Hi @sachinaror2435 

Can you please try to reboot server or you can follow below link seems same issue:

https://magentoexplorer.com/magento-2-error-503-backend-fetch-failed-how-to-fix