Solved: Varnish 4 “Internal Server Error 500”

by Danila Vershinin, February 27, 2016

Why Varnish returns “Internal Server Error 500” Once you done writing your VCL for Varnish 4, you may not be aware that it silently fails with 500 Internal Server Error for some requests. Most likely, the reason is client workspace overflow. When you run varnishlog and watch for requests, you will see: “LostHeader” and “workspace_client […]