Reverse proxy setup problem

I have created a reverse proxy for 2 web servers both are running about
sites each, they use to be on seperate external IP’s but now need to be
behind the same one.

Using Nginx I setup a reverse proxy on a seperate VM, Its seems to work
one site is refusing to go to the correct server.

I have nothing in /conf.d/ I am using /sites-available and
each site has its own config file. Im using proxy_pass with the servers
address. What am I doing wrong?

server {
location / {
proxy_redirect off;
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_max_temp_file_size 0;
client_max_body_size 10m;
client_body_buffer_size 128k;
proxy_connect_timeout 90;
proxy_send_timeout 90;
proxy_read_timeout 90;
proxy_buffer_size 4k;
proxy_buffers 4 32k;
proxy_busy_buffers_size 64k;
proxy_temp_file_write_size 64k;

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