Fix u2f with nginx rp

docs/first_steps.md

@@ -126,7 +126,6 @@ server {
     location / {
         proxy_pass http://127.0.0.1:8080/;
         proxy_redirect http://127.0.0.1:8080/ $scheme://$host:$server_port/;
-        proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         proxy_set_header X-Forwarded-Proto $scheme;