Nginx redirection from www to non-www - nginx

Question

I have an issue with redirecting from www to non-www.
My expected behaviour: all requests on port 80 and 443 should be redirected to non-www.
I also have a subdomain dev.example.com requests on this subdomain should also be redirected to non-www.
All is working fine with my current configuration except one thing:
If I request http://example.com then i'll be redirected to https://dev.example.com and i cannot find the reason for that.
Can anyone tell me what i did wrong?
I have 3 conf files in my nginx sites-enabled directory linked:
first :
server {
listen 80 default_server;
listen [::]:80 default_server;
server_name example.com www.* dev.*;
return 301 https://$host$request_uri;
}
server {
listen 443 default_server ssl;
listen [::]:443 ssl;
server_name example.com;
root /var/www/my-site/public;
# Path of the SSL certificate
ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
# Use the file generated by certbot command.
include /etc/letsencrypt/options-ssl-nginx.conf;
# Define the path of the dhparam.pem file.
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
disable_symlinks off;
add_header X-Frame-Options "SAMEORIGIN";
add_header X-Content-Type-Options "nosniff";
index index.php index.html;
charset utf-8;
location / {
try_files $uri $uri/ /index.php?$query_string;
}
location = /favicon.ico { access_log off; log_not_found off; }
location = /robots.txt { access_log off; log_not_found off; }
error_page 404 /index.php;
location ~ \.php$ {
fastcgi_pass unix:/var/run/php/php8.0-fpm.sock;
fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name;
include fastcgi_params;
}
location ~ /\.(?!well-known).* {
deny all;
}
}
second:
server {
listen 443 ssl;
listen [::]:443 ssl;
server_name dev.example.com;
root /var/www/my-dev-site/public;
# Path of the SSL certificate
ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
# Use the file generated by certbot command.
include /etc/letsencrypt/options-ssl-nginx.conf;
# Define the path of the dhparam.pem file.
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
disable_symlinks off;
add_header X-Frame-Options "SAMEORIGIN";
add_header X-Content-Type-Options "nosniff";
index index.php index.html;
charset utf-8;
location / {
try_files $uri $uri/ /index.php?$query_string;
}
location = /favicon.ico { access_log off; log_not_found off; }
location = /robots.txt { access_log off; log_not_found off; }
error_page 404 /index.php;
location ~ \.php$ {
fastcgi_pass unix:/var/run/php/php8.0-fpm.sock;
fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name;
include fastcgi_params;
}
location ~ /\.(?!well-known).* {
deny all;
}
}
third(for mailserver):
server {
if ($host = autoconfig.example.com) {
return 301 https://$host$request_uri;
} # managed by Certbot
if ($host = autodiscover.example.com) {
return 301 https://$host$request_uri;
} # managed by Certbot
if ($host = mail.example.com) {
return 301 https://$host$request_uri;
} # managed by Certbot
listen 80;
listen [::]:80;
server_name mail.example.com autodiscover.* autoconfig.*;
return 301 https://$host$request_uri;
}
server {
listen 443 ssl http2;
listen [::]:443 ssl http2;
server_name mail.example.com autodiscover.* autoconfig.*;
# Path of the SSL certificate
ssl_certificate /etc/letsencrypt/live/steamangel.de/fullchain.pem; # managed by Certbot
ssl_certificate_key /etc/letsencrypt/live/steamangel.de/privkey.pem; # managed by Certbot
# Use the file generated by certbot command.
include /etc/letsencrypt/options-ssl-nginx.conf;
# Define the path of the dhparam.pem file.
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
location /Microsoft-Server-ActiveSync {
proxy_pass http://127.0.0.1:8080/Microsoft-Server-ActiveSync;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_connect_timeout 75;
proxy_send_timeout 3650;
proxy_read_timeout 3650;
proxy_buffers 64 256k;
client_body_buffer_size 512k;
client_max_body_size 0;
}
location / {
proxy_pass http://127.0.0.1:8080/;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
client_max_body_size 0;
}
}