Clean nginx config

etc/nginx/sites-enabled/mail

@@ -50,7 +50,7 @@ server {
 	add_header Cross-Origin-Embedder-Policy require-corp always;
 	add_header Cross-Origin-Opener-Policy same-origin always;
 	add_header Cross-Origin-Resource-Policy same-origin always;
-        listen [::]:443 ssl proxy_protocol http2;
+	listen [::]:443 ssl http2;
 	ssl_certificate /etc/ssl/certs/ssl-cert-snakeoil.pem;
 	ssl_certificate_key /etc/ssl/private/ssl-cert-snakeoil.key;
 	root /var/www/html;