magento2 – emerg duplicate upstream “fastcgi_backend”

I’m setting up a vhost for my magento site. So basically I have 2 store namely store1 and store2. Since this 2 store is using the same code and DB I setup the vhost in NGINX almost identical. The only difference are their server_name now when I try to restart my nginx I get the emerg duplicate upstream "fastcgi_backend" error. Not sure what happen. Below is my code

upstream fastcgi_backend {
    server unix:/var/run/php/php7.4-fpm.sock;
}

server {
    listen 80;
    listen 443 ssl http2;
    server_name site1.com.test;
    set $MAGE_MODE developer;
    set $MAGE_ROOT /home/vagrant/code;
    include /home/vagrant/code/nginx.conf.sample;

    index index.html index.htm index.php;
    sendfile off;

    location ~ .php$ {
        fastcgi_split_path_info ^(.+.php)(/.+)$;
        fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_intercept_errors off;
        fastcgi_buffer_size 16k;
        fastcgi_buffers 4 16k;
        fastcgi_connect_timeout 300;
        fastcgi_send_timeout 300;
        fastcgi_read_timeout 300;
    }

    location ~ /.ht {
        deny all;
    }

    ssl_certificate     /etc/nginx/ssl/site1.com.test.crt;
    ssl_certificate_key /etc/nginx/ssl/site1.com.test.key;
}

And here is my conf for the second site

upstream fastcgi_backend {
    server unix:/var/run/php/php7.4-fpm.sock;
}

server {
    listen 80;
    listen 443 ssl http2;
    server_name site2.com.test;
    set $MAGE_MODE developer;
    set $MAGE_ROOT /home/vagrant/code;
    include /home/vagrant/code/nginx.conf.sample;

    index index.html index.htm index.php;
    sendfile off;

    location ~ .php$ {
        fastcgi_split_path_info ^(.+.php)(/.+)$;
        fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_intercept_errors off;
        fastcgi_buffer_size 16k;
        fastcgi_buffers 4 16k;
        fastcgi_connect_timeout 300;
        fastcgi_send_timeout 300;
        fastcgi_read_timeout 300;
    }

    location ~ /.ht {
        deny all;
    }

    ssl_certificate     /etc/nginx/ssl/site2.com.test.crt;
    ssl_certificate_key /etc/nginx/ssl/site2.com.test.key;
}

So it’s almost identical except for the servername. But I have no idea why I’m getting this error emerg duplicate upstream "fastcgi_backend"

Would really appreciate any help here.

Note: I only tried just 1 config in the site-enabled and the config was working. Only when I try to load/enable a second site that I experience that error