Web server gone after installing nginx

I thought installing a reverse proxy server was a good security layer for my network,

but I lost access to the pi hole web interface :

403 Forbidden

nginx/1.10.3 (Ubuntu)

How can I get it back without interfering on the proxy server?

I rune curl -sSL https://install.pi-hole.net | bash again and did a update but no luck

resolved, the issue I had was with the firewall