Why, when configuring my nginx, I don't see what I want to see?

Question

Nginx

There is a configuration, and it does not work properly - not the way I would like it. What could be the problem? I suspect that the problem lies not in nginx at all, but in my system, help me solve my question.
So here is the configuration:

server {
  listen 80;
  server_name 127.0.0.1;

  location / {
    root /var/www;
    index index.html;
  }
}

server {
  listen 80;
  server_name api.127.0.0.1;

  location / {
    proxy_pass http://0.0.0.0:8080;
    proxy_redirect off;
  }
}

What do I expect? When switching to api.127.0.0.1, I expect to hear a response from the server (I don’t hear it). When I change the port from 80 to 81, I hear. I'm almost sure that something is wrong with the addressing in the system (network settings). How can I identify the cause of the problem, and thereby solve my problem?
my ifconfig:

eth0      Link encap:Ethernet  HWaddr 00:1a:4d:91:2b:c0  
          inet addr:192.168.1.153  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::21a:4dff:fe91:2bc0/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1598553 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1062272 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1861495927 (1.8 GB)  TX bytes:456603051 (456.6 MB)
          Interrupt:41 

lo        Link encap:Локальная петля (Loopback)  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:19673 errors:0 dropped:0 overruns:0 frame:0
          TX packets:19673 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:9471669 (9.4 MB)  TX bytes:9471669 (9.4 MB)

upd1: added ifconfig

Answer 1

What for?? Why api.127.0.0.1? What did they use?

Answer 2

don't get what you expect. or not what you expect, what you need.
127.0.0.1 is the ip address. although this is also a loopback interface. And you are trying to make a sub-domain that uses an ip address as the domain of the top address.
I think what you need is:
nginx config:
server_name myserver;
...
server_name api.myserver;
and in /etc/hosts:
127.0.0.1 myserver
127.0.0.1 api.myserver
and then in the browser myserver or api.myserver