Why does nginx redirect to port 80 if listen 7777 is set?

Question

Nginx

Centos + Nginx + httpd
The essence of the problem:
The first input on which the back works on port 8080, and the front on 80

nginx vhost1

server {
listen 80;
server_name ********;
#access_log /website/name.site/logs/nginx_access.log;
error_log /var/www/crmMSK/logs/nginx_error.log;

location / {
proxy_pass http://127.0.0.1:8080/;
proxy_read_timeout 300s;
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_buffering off;
}

location ~* \.(css|js|png|gif|jpg|jpeg|ico)$ {
root /var/www/crmMSK;
expires 1d;
}

location ^~ /phpmyadmin/
{
proxy_pass http://127.0.0.1:8080;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_connect_timeout 120;
proxy_send_timeout 120;
proxy_read_timeout 180;
}

error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
}

httpd1

<VirtualHost *:8080>
 ServerName *********
 DocumentRoot /var/www/crmMSK
 <Directory /var/www/crmMSK>
 Options FollowSymLinks
 AllowOverride All
 Require all granted
 </Directory>
 ErrorLog /var/www/crmMSK/logs/error.log
 CustomLog /var/www/crmMSK/logs/access.log common
</VirtualHost>

Second input, back on port 8081, front on port 7777

nginx vhost2

server {
listen 7777;
server_name ********;
#access_log /website/name.site/logs/nginx_access.log;
error_log /var/www/crmMSK/logs/nginx_error.log;

location / {
proxy_pass http://127.0.0.1:8081/;
proxy_read_timeout 300s;
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_buffering off;
}

location ~* \.(css|js|png|gif|jpg|jpeg|ico)$ {
root /var/www/crmMSK;
expires 1d;
}

location ^~ /phpmyadmin/
{
proxy_pass http://127.0.0.1:8081;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_connect_timeout 120;
proxy_send_timeout 120;
proxy_read_timeout 180;
}

error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
}

httpd2

<VirtualHost *:8081>
 ServerName *******
 DocumentRoot /var/www/crmBLR
 <Directory /var/www/crmBLR>
 Options FollowSymLinks
 AllowOverride All
 Require all granted
 </Directory>
 ErrorLog /var/www/crmBLR/logs/error.log
 CustomLog /var/www/crmBLR/logs/access.log common
</VirtualHost>

so, the first input works as it should, but the second one redirects to 80 instead of 7777

Answer 1

Check the back, and specifically its config, I don’t know what is there, but in this whole bunch, only the back can do this.
Although the front can, but there is less chance of fixing it.