"General socket error" when Nginx behind HAProxy using a unix socket

I had the same problem with Haproxy 1.8.19 on Debian Buster with Varnish 6.0.3 as backend.

For me, the problem come from chroot option in Haproxy configuration :

chroot /var/lib/haproxy

You have two solutions to fix this :

• Move your's Nginx Unix socket in chroot directory

• Or disable chroot option, but it's not recommended for security reason.