Error "proxy_redirect" directive is duplicate in /etc/nginx/privx/privx-proxy-headers.conf:3

Symptom

PrivX postinstall scripts encounter following errors
"proxy_redirect" directive is duplicate in /etc/nginx/privx/privx-proxy-headers.conf:3"

Workaround

Edit file /etc/nginx/privx/privx-https-location.conf, and remove all occurrences of following lines
proxy_redirect off;