give access after proxy_pass

Hello
I have this simple setting :
server {
listen 80 default_server;
listen [::]:80 default_server;
server_name _;
root /usr/share/nginx/html;

# Load configuration files for the default server block.
include /etc/nginx/default.d/*.conf;
location /FirstPage.html {
#proxy_set_header Host $http_host$request_uri;
proxy_pass http://172.16.254.120/;
#proxy_read_timeout 120s;
#access_log on;

}

location /error.html {
internal;
}

error_page 404 /404.html;
location = /40x.html {
}

error_page 500 502 503 504 /50x.html;
location = /50x.html {
}
}


now , when I enter FirstPage.html - he redirect me to 172.16.254.120
but when I want to enter other pages after it - I get error message
"The pgae you are looking for is not found "
how to fix this?
what I need to add to allow me to work in 172.16.254.120?

Thanks ,